In answering the question of Usability, "Can I use it?" the sub-category of Page Load plays an instrumental part. Twitter is one such excellent example of a web product with Poor Page Load Time.

A company can have the best product around, but if the pages are too sluggish, if the product suffers recurring outages, if the user-product interaction is varied and inconsistent, the product’s overall Usability can, and does, suffer.

Quick-UX provides for the rapid, simple and quantifiable assessment of a product’s User Experience (UX). Among the various components that define a product’s Usability, as well as Quick-UX‘s, are Accessibility, Consistency, Recognition, Navigation, and Page Load Time.

In answering the question of Usability, "Can I use it?" the sub-category of Page Load plays an instrumental role. Page Load, often obfuscated or connected with other perceived causes of a product’s dissatisfaction, ultimately, either positively or negatively, presents an unquestionable influence on a product’s overall Usability.

Example: Poor Load Time (value = 0.0)

Twitter is fast becoming, and for some already is, an essential communication tool.

Yet, Twitter earns a Page Load Time variable value of 0, due to its intermittent slow performance, but more so contributing to this value are the constant outages felt through the year, month after month.

If the page doesn’t load, if requested action takes an interminable amount of time, if the likelihood of the next user action failing is constantly looming, the overall Usability of a product takes a terrible toll.

In 2009, according to Pingdom, Twitter experienced a total of 20.82 hours of downtime.

Outages of Twitter were not isolated to merely the entire site being unavailable, but also consisted of sub-sections, or sub-features not working or resulting undesirable or unexpected behavior. Contributing to the pervasive problem of Page Load Time is both the inaccessibility of the product as well as the inability of the users to obtain key information (missing updates, etc) and other bugs leading to incomplete or otherwise incorrect Page Loads.

A Quick Study

I quickly examined and compiled a list of incidents that affected the Page Load Time of the Twitter product, distinguishing between total downtime, and partial downtime and information inaccessibility, based upon the public posts on Twitters blog.

I did my best to not double count any problems, but it was difficult since many of the problems occur so frequently, and it is often difficult to distinguish, from these status blog posts alone, between a persisting problem being experienced or fixed, from that of a new emergence of a similar or same problem. Furthermore, I also excluded the impact on Page Load Time arising from scheduled maintenance/downtime – periods of time over which the user expectation would be most aligned with the product’s promise of Page Load Time.

Some of my notes regarding my review of Twitter’s 2009 product Page Load Issues…

Dec 17 Site Outage DNS records compromised http://status.twitter.com/post/288586541/working-on-site-outage Dec 14 sms service unavailable http://status.twitter.com/post/283934158/sms-service-temporarily-unavailable-we-are-working-on Dec 8 unplanned downtime http://status.twitter.com/post/275824585/responding-to-unscheduled-downtime Dec 7 unplanned downtime http://status.twitter.com/post/273515629/brief-downtime Dec 6 high rate of failwhales http://status.twitter.com/post/272315876/responding-to-whales

Nov 30 Unplanned downtime high error rate; tmp disabled list feature http://status.twitter.com/post/263867698/responding-to-high-error-rate-lists-feature Nov 23 elevated error rate http://status.twitter.com/post/254725789/fixing-elevated-error-rate-on-twitter-com Nov 11 high number of errors http://status.twitter.com/post/240542434/working-on-high-number-of-errors Nov 6 elevated errors http://status.twitter.com/post/235296654/were-looking-into-the-cause-of-elevated-errors-on-the

Oct 21 elevated error rate http://status.twitter.com/post/219264090/elevated-error-rate-being-worked-on Oct 18 network connectivity problems http://status.twitter.com/post/216351172/responding-to-network-connectivity-problems Oct 13 account lockouts after username/pw change http://status.twitter.com/post/212318608/researching-username-password-change-problems Oct 12 errors and inability to tweet http://status.twitter.com/post/211258987/responding-to-increased-errors-inability-to-tweet Oct 7 Unplanned downtime http://status.twitter.com/post/207018761/recovering-from-unplanned-downtime

Sept 10 site slowness http://status.twitter.com/post/185079863/working-through-site-slowness Sept 9 secure connection failed issues http://status.twitter.com/post/183975122/secure-connection-failed-issues

August 24 unexpected service interruption http://status.twitter.com/post/170695014/we-are-responding-to-an-unexpected-service-interruption August 16 Oauth and API problems http://status.twitter.com/post/164410057/trouble-with-oauth-and-api-clients August 15 unexpected downtime http://status.twitter.com/post/163603406/working-on-unexpected-downtime August 11 Site outage http://status.twitter.com/post/160693237/responding-to-site-downtime August 6 Site is down DOS attack http://status.twitter.com/post/157160617/site-is-down http://status.twitter.com/post/157191978/ongoing-denial-of-service-attackhttp://status.twitter.com/post/157191978/ongoing-denial-of-service-attack August 2 Search Down problem coming from migrating data centers http://status.twitter.com/post/44516325/twitter-search-temporarily-down

July 10 site latency widespread http://status.twitter.com/post/139238308/working-on-site-latency July 5 restoring accidentially suspended accounts http://status.twitter.com/post/136164828/restoring-accidentally-suspended-accounts

June 15 Outage problem w/ maintenance by provider http://status.twitter.com/post/124145031/maintenance-window-tonight-9-45p-pacific

May 30 unscheduled downtime fatal software error http://status.twitter.com/post/115523264/unscheduled-downtime May 28 unable to create new accounts captcha problem http://status.twitter.com/post/114566780/unable-to-create-new-accounts May 27 site latency http://status.twitter.com/post/113959453/working-through-site-latency May 27 Unplanned downtime http://status.twitter.com/post/113891094/recovering-from-unplanned-downtime May 22 search down http://status.twitter.com/post/111769727/search-temporarily-down May 21 robot errors http://status.twitter.com/post/111054487/fixing-robot-errors May 20 user search unavailable http://status.twitter.com/post/110639419/user-search-temporarily-unavailable May 14 unplanned downtime http://status.twitter.com/post/107824532/unplanned-downtime May 8 latency issues resulting from a scheduled site maintenance http://status.twitter.com/post/105202075/back-from-site-maintenance-working-on-site-latency

Apr 28 elevated error rate fail whales http://status.twitter.com/post/101237008/fixing-the-elevated-error-rate Apr 13 slow load times and high error rates http://status.twitter.com/post/95787359/responding-to-slow-load-times-and-high-error-rates Apr 9 high latency also fb not updating http://status.twitter.com/post/94536362/twitter-com-is-experiencing-high-latency-were-also Apr 7 high site errors; downtime/load issues http://status.twitter.com/post/93850673/update-on-delivery-delays-errors Apr 6 maintenance (no advance warning); downtime http://status.twitter.com/post/93641925/one-hour-maintenance-starting-at-5-45p-pacific Apr 6 errors; downtime fail whales, robot pages; missing tweets http://status.twitter.com/post/93501130/working-through-some-errors-this-morning Apr 3 errors; downtime fail whales, robot pages http://status.twitter.com/post/92659539/recovering-from-errors-this-morning

Mar 16 unplanned maintenance widespread slowness http://status.twitter.com/post/87009894/unplanned-maintenance Mar 4 problems logging in http://status.twitter.com/post/83602310/problems-logging-in Mar 2 power failure degraded performance http://status.twitter.com/post/82874378/power-failure-this-morning

Feb 18 latency issues very long load times http://status.twitter.com/post/79456053/working-on-site-latency-issues Feb 14 downtime db problem http://status.twitter.com/post/78228774/back-from-maintenance-mode Feb 11 Site down db problem http://status.twitter.com/post/77438630/site-back-up

Jan 20 site slow slow load times http://status.twitter.com/post/71824634/slowness Jan 16 downtime notified user of potential for more downtime http://status.twitter.com/post/70991844/twitter-downtime

Dec 17 timeline delays and missing tweets http://status.twitter.com/post/287676075/known-issues-timeline-delays-and-missing-tweets Dec 10 problem posting tweets to FB problem resulting from FB latency issues http://status.twitter.com/post/277958642/not-all-tweets-from-facebook-app-being-posted-to

Nov 5 missing mentions http://status.twitter.com/post/234412987/missing-some-mentions

Oct 28 no dmsg emails http://status.twitter.com/post/226186595/not-receiving-emails-for-direct-messages Oct 15 timelines 0.5h behind http://status.twitter.com/post/214053142/timelines-currently-30-minutes-behind Oct 8 timeline delays bug http://status.twitter.com/post/207632462/timeline-delays-this-morning

Sept 16 missing tweets bug http://status.twitter.com/post/189862465/tweets-from-users-you-follow-may-be-missing-from-your Sept 14 missing tweets for some http://status.twitter.com/post/187786359/missing-tweets-from-some-users Sept 4 short delivery delays http://status.twitter.com/post/179752377/working-on-short-delivery-delays Sept 2 some tweets & followings delayed small subset? http://status.twitter.com/post/178076369/some-tweets-and-followings-delayed

August 12 timeline delays http://status.twitter.com/post/161638570/working-on-timeline-delays

July 28 missing followers for new users http://status.twitter.com/post/151217980/working-on-missing-followers-for-recently-joined-users

June 29 viewing other people followers/following disabled bug http://status.twitter.com/post/132761078/viewing-other-peoples-followers-and-followings June 16 unable to find new users http://status.twitter.com/post/124832153/working-to-get-new-users-into-find-people June 12 search delay new tweets not being picked up by search http://status.twitter.com/post/122606485/search-delay June 3 delayed followings resulting from spam attack http://status.twitter.com/post/117482837/delayed-followings

May 13 timeline delays hardware failure http://status.twitter.com/post/107561169/temporary-timeline-delays May 4 search running behind search not processing real-time http://status.twitter.com/post/103533181/search-running-behind

Apr 22 data inconsistencies bug [still being fixed on the 27th] http://status.twitter.com/post/99180872/tracking-down-data-inconsistencies Apr 22 missing user images http://status.twitter.com/post/98960090/missing-user-images Apr 14 delayed search results http://status.twitter.com/post/96196695/search-results-are-delayed-about-20-minutes Apr 10 missing updates http://status.twitter.com/post/94970050/were-working-to-resolve-an-issue-with-some-missing Apr 6 missing avatars and dmsgs http://status.twitter.com/post/93589702/missing-user-icons-avatars-and-direct-messages Apr 2 not finding self in people search bug http://status.twitter.com/post/92334992/not-finding-yourself-in-people-search

Mar 18 missing tweets db inconsistency, etc. http://status.twitter.com/post/87625680/some-users-experiencing-missing-tweets Mar 16 Delays on following and dmsgs http://status.twitter.com/post/86986973/some-delays-on-followings-direct-messages Mar 12 missing updates & actions http://status.twitter.com/post/86067236/some-missing-updates-actions Mar 11 inconsistencies data inconsistencies (msg, counts, other data) http://status.twitter.com/post/85644965/update-on-inconsistencies Mar 9 inbound sms delay http://status.twitter.com/post/84921942/inbound-sms-delay

Feb 6 inconsistent follower/following counts http://status.twitter.com/post/76219963/delays-in-posting-text-messages Feb 6 txt msg posting delays problem w/ provider http://status.twitter.com/post/76219963/delays-in-posting-text-messages Feb 2 Missing updates http://status.twitter.com/post/75182201/missing-updates-were-bringing-them-back Feb 2 missing self new users missing from search http://status.twitter.com/post/75102341/unable-to-find-yourself

Jan 30 follower/following counts wrong due to replication lag http://status.twitter.com/post/74360199/were-looking-into-inconsistencies-with Jan 19 slow search search fell behind realtime due to maintenance http://status.twitter.com/post/71697063/search-behind-realtime Jan 8 Delivery delays tweets slow to appear in the timeline http://status.twitter.com/post/69184677/catching-back-up Jan 6 Delivery delays tweets slow to appear in the timeline http://status.twitter.com/post/68751921/delivery-delays

That said, a clear picture of the Page Load Time experience felt by the Twitter product’s user base quickly emerged.

Approximately 14% of all days in the year experienced delays and disruptions, directly altering the Page Load Time of the product. And, another ~10% of the year’s days experience pages loading with missing information, resulting in a total number of days experiencing disruption at around 24% of the year or 86 days! (note: there may be some day overlap that is not taken into account in these numbers)

Note: Data for December is complete (only goes through December 21, 2009)

Should Do & A Clear Flight Path

When using Twitter, tweets, responses, searches can and sometimes do occur quickly and without incident. However, with such consistency of problematic service, fail whales, site latency, etc. Twitter earns no more than a value of 0 for Page Load Time; but with a clear path to improvement…

first, focus on the reliability of the Page Load , drastically reducing downtime,

, drastically reducing downtime, then, focus on the missing data and other inconveniences, some of which are touched upon in my table of notes above.

Next…

Over the next several weeks I will be providing real-world examples of Page Load Time values…

Poor Load Time (value 0) [Twitter, Twine]

Delayed Load Time (value 0.5) [Conversation Pieces]

Prompt Load Time (value 1) [Facebook]

Subscribe now (click here) to make sure you don’t miss any part of this series exploring the Usability and Page Load Time of Quick-UX, the quick and easy method of generating quantifiable and comparable metrics representing the understanding of the overall User Experience of a product, as well as other insightful posts from The Product Guy.

Enjoy, Discuss & Tweet!

Jeremy Horn

The Product Guy

Add to Social Bookmarks: