Andy Warhol talked of a time when everyone would be famous for 15 minutes. With hindsight, however, he might have wanted to revise that down to about five minutes. On today's web, phrases such as "here today, gone tomorrow" seem to involve ridiculously long timescales.

People who moaned that blogging represented a move to shorter attention spans – 250-to-350-word posts rather than 1,000-word stories – have now seen blog posts start to look big and, frankly, old-fashioned. Today's trendsetters are using "microblogging" sites such as Tumblr, Posterous and Soup.io, which are taking the opportunity for creative "borrowing" to new heights.

But the smash hit of 2009 has been (apologies: I know this will cause pain) Twitter, where 1,000-word stories are reduced to 140-character tweets. Short attention spans R us.

Twitter's rapid growth and open programming interface have given the site a wide impact. Hundreds, possibly thousands, of ancillary sites and services have been launched to help Twitter users post pictures, track followers, or – more usefully, from a commercial point of view – find out what the "hive mind" is thinking. Twitterfall is just one example. More recently, Listorious stepped in to make it easier to find and explore lists made using Twitter's new list feature, while The Twitter Tim.es cleverly turned selected tweets into a personalised newspaper. How many of these sites will survive is, of course, open to question. Some are less like standalone sites than parasites.

Major web players such as Facebook, Google, and Microsoft also got involved. Both Google and Microsoft signed deals for Twitter searches, while Facebook paid it the ultimate compliment of more or less copying its service. Or, perhaps, copying FriendFeed, which many users link to both Twitter and Facebook.

Facebook, while far from new, was another big player in 2009, reaching more than 350 million users. And through Facebook Connect, it has extended its presence across the web. Once you have a Facebook identity – and you must have one, mustn't you? – then you can use it to access a growing number of sites and services. And that's not necessarily a bad thing. The web might be a kinder, more polite place if people said things under their real names, which is what Facebook's about.

Those in search of their five minutes of fame or, more likely, five minutes of fun fun fun, headed for YouTube. Although it has been challenged by rivals such as Vimeo and Microsoft's Soapbox (RIP), its dominance has not been seriously threatened. Only the pornographers have been able to build much of a following outside YouTube.

Which is not to say that YouTube owns the web video market. The BBC has made a huge impact with its iPlayer catchup service, and in the US, Hulu has enjoyed great success with TV series and movies. Of course, both sites are showing videos that YouTube would love to offer, at a profit, and it will be interesting to see how this plays out.

Music has been a significant player in the growth of the web since Napster, and its influence continues to grow. Spotify has made the biggest impact this year, gaining mindshare lost by Last.fm and Pandora. Meanwhile, Pitchfork has expanded its role as the web's authoritative music magazine, and The Hype Machine came to prominence as a source of instant erudition by tracking the music blogs.

Almost finally, it may be that we are seeing the return not just of the browser wars but of the search engine wars as well. Google still rules the world, but in Bing, it now has a competitor that does some things better and has, in Microsoft, an owner with deep pockets. Alas, Bing also does many things a lot worse.

Possibly the most contentious part of this year's list is celebrity gossip. The argument against would be summed up by a Wikipedian in two words: "not notable". The argument for is that sites such as Perez Hilton and AOL's TMZ are now helping to drive the news agenda. Even if you aren't interested in Michael Jackson's death, Tiger Woods's affairs or whatever, this stuff has become impossible to avoid. This is one case where many people would prefer the web's short attention span to be even shorter.

Blogging/microblogging

Now easier than falling off a log.

Tumblr Multimedia microblogging plus Twitter-style following.

Posterous Goes from instant microblogging into lifestreaming.

Soup A "super-easy" tumblelog for scrapbook keeping and lifestreaming.

Blogger Fast way to start blogging; training wheels for Wordpress.

Bloglines For reading web feeds. Smart and clean.

Wordpress Free, and most importantly spam-free, blogging.

Browsers

Do we all need five browsers nowadays?

Chrome Now here for Mac, and anticipating future world domination via Chrome OS.

Firefox Everyone's favourite is under attack from all sides.

Maxthon Based on IE code. If it stays "hip in China" it could reach a large global audience.

Cartoons

Everyone needs some relaxation. This is a visual one.

Dilbert It wouldn't be so funny if it wasn't so true.

XKCD Stick-figure strip poking fun at geek topics and relationships.

Celebrity gossip

No one needs this stuff, but it's starting to drive world news and web traffic.

TMZ Rose to fame when it broke news of Michael Jackson's death.

Perez Hilton Among the bitchiest of goss sites and often involved in 'interesting' celeb baiting.

Gawker New York-based media alert and gossip blog network, with fingers in many pies.

Create/collaborate

With all of us now living more of our lives online, these sites just scratch the surface.

Netvibes Your to-do lists, news, weather and photos on one page.

Scribd Shares 35bn words online: they can't all be wrong.

Slideshare Like YouTube for PowerPoint decks.

Zamzar Useful: converts files from one format to another.

Film

Sites to see before heading for the latest blockbuster at your local multiplex.

IMDb The most authoritative site about all things film and TV, which is why Amazon bought it.

Rotten Tomatoes Collects online film reviews, aggregates a score out of 100 and rates the film "fresh" or "rotten".

/Film Said to be the favourite film blog of directors Jason Reitman and Darren Aronofsky, /Film features news, reviews, interviews and a special UK update each Friday.

Cinematical Terrific film blog with a Hollywood focus.

Gaming

A field where handheld, bedroom and Flash games are becoming mainstream

Eurogamer Reportage, with breadth, if not always depth.

The Independent Gaming Source A great place to pick up on tomorrow's breakthrough Xbox Live Arcade, WiiWare and PSN hits.

Pocket Gamer Still by far the best site on handheld gaming.

Gamasutra Where professional games creators hang out, and sometimes get jobs

Geek squad

Here be programmers …

Stack Overflow Where programmers gather to try to solve their problems.

The Daily WTF Daily dispatches from the coding warzone.

Joel On Software Essays by a former Microsoftie, now head of Fog Creek Software.

Government/public services/politics

Recycle Now Winner after a slight false start of the government'sShow Us A Better Way competition. What can you recycle close by?

British and Irish Legal Information Institute A database of laws. Only survives hand-to-mouth on voluntary donations; where's yours?

What Do They Know? Makes filing a Freedom Of Information request as easy as sending an email. Too easy, some in power think.

Upmystreet All the detail on your area you could ever want.

They Work For You A site set up by volunteers to keep tabs on our elected members of parliament – and our unelected peers.

Link economy

With millions of links on the web, we all need sites for sharing the best ones.

Digg Still the reigning champion of where the latest internet memes are though not always polite.

Delicious The thinking person's link aggregation site. We use it.

Popurls Aggregating the aggregators: the web in a window.

Metafilter Living if isolated proof that a site can be successful without pictures or video, and can also host thoughtful conversations.

Slashdot Now looking venerable and old, but "News for nerds" site with a jokey name (/.) still attracts a big, and often knowledgable, audience.

Techmeme Technology news chosen by computer, though it's now refined by human editors.

Location, location

Services like these blossom with a mobile phone that can access the internet.

Dopplr "Share your future travel plans with friends and colleagues", then find out if others will be there too.

Qype Localised search for pubs, restaurants, etc; also a bit of a social network.

Loopt "Transforms your mobile phone into a social compass".

Brightkite A "location-based social network".

Maps

The flipside of location-based services: seeing where you are.

OpenStreetMap A rights-free map created by people like you. Remarkably detailed and precise.

Google Maps Street View Virtual tourism with practical applications, too.

Money/finance/consumer fightback

We all need someone on our side.

Money Saving Expert Does what it says on the tin.

Say No to 0870 Direct-dial numbers, not expensive national-rate ones.

Consumer Direct Government site for consumers.

Music

Last.fm British-made, now CBS-owned, music recommendation station.

Amazon Now has its own MP3 store in the UK as well as the US.

Hype Machine Picks up the latest news by tracking the music blogs.

Pitchfork The magazine of the music web, now with video, and lots of great lists.

Offbeat

The Onion Still the satirical newspaper of record. If it's not in the Onion, it's probably happened.

B3TA Beyond classification; its forum has spawned many memes … and more than its fair share of trolls.

Lolcats respite from stress with daft cCaptioned cats and other animals.

News Lite respite from stress with daft cGreat source of news that's much too trivial to print.

Oddee Setting an internet standard for sets of curious and mildly amusing pictures, not cats.

PostSecret Notes of secrets sent by people who want them posted. So they are.

Passive-Aggressive Notes Would it be too much trouble for you to have a look?

Photography

Flickr The granddaddy of photo-sharing sites.

Picnik Photo editing in your browser.

Picasa Google's photo organisation and editing tool.

DPreview The web's best guide to cameras. Now Amazon owned.

Reference

CIA Factbook All the data you need on pretty much anywhere.

Wikipedia en.wikipedia.com the gradually growing user-edited encyclopaedia is Still a first port of call on most topics.

Internet Archive/Wayback Machine The web in aspic. Useful for research into how the web used to look.

Metacritic Aggregates reviews of movies and DVDs, TV programmes, music and games

Wikileaks Anonymous source of a huge range ofleaked documents. If you dig, there's something important there

Search

Google dominates but Bing is challenging, and Yahoo and Microsoft are left in the dust.

Google So good it's become almost synonymous with search.

Bing Microsoft would like you to bing it, but its "decision engine" still has a long way to go.

Wolfram Alpha An "answer engine"that delivers when it has the data, but not that easy to use.

Social software

Two years ago it was nascent; now it's embedded in our culture. Chances are high you're a member of at least one, and perhaps all, of these sites.

Facebook Still changing and growing to become not just your home on the web, but your ID provider.

LinkedIn Contact sports for business users.

Ning One place to start your own social network – just as Madonna did – though it has yet to really take off.

Travel

Expedia Still the daddy when it comes to travel sites, and particularly good if you can bundle a flight with a hotel and other services.

TripAdvisor Essential reading for the user reviews of hotels, but it now covers much more.

Laterooms Specialises in hotel discounts.

Twitter, and associated

Twitter has proved itself over and over this year, from the Chinese earthquke to the Mumbai attacks to the Madoff fraud as a vector for news.

Twitter The ur-site, where you can create an identity (or several).

Twitter Tim.es Creates your personal newspaper based on your friend's tweets.

Twitterfeed Posts blog contents to Twitter.

TwitterCounter Graphs the growth in your followers.

Twitterfall Tracks trending topics; enables custom searches.

Listorious Twitter lists make it simple to follow large groups of Twitter users, and Listorious makes it easy to find the best lists.

Video

YouTube Dominant provider of video content online.

Vimeo Better rights control than YouTube and a cleaner interface

BBC iPlayer The king of the online catchup services.

Hulu The networks fight back with their own video site, which may make the UK in 2010. We hope.

Videojug The motherlode of instructional videos, all in one place.

Virtual worlds

Second Life Continues to exist and is, apparently, still popular, but not the media darling it was.

Entropia Universe Set in a distant future on the untamed planet of Calypso.

Club Penguin Minigame-tastic virtual world for youngkids.

Moshi Monsters "Educational" virtual world for kids.

Visual arts

Saatchi Gallery Gallery, listings and artworks for sale.

Art Daily The first "art newspaper" on the net.

Culture 24 Everything about UK galleries and museums.

Visualisation

Information is Beautiful Creating effective infographics is one of today's key skills, and on this site, it's also an art.

Infosthetics.com An archive of some of the finest examples of "information aesthetics".

DabbleDB Create online databases and analyse them.



• Which essential sites have we missed? Tell us below

• This article was amended on Wednesday 9 December 2009. Picasa is no longer for Windows only; Streetwire.org is no longer operational. These have been corrected.