It's no stretch to say that ads are what make the Web go 'round. The content you're reading right now? Paid for by ads. Google, Facebook, Pandora, YouTube? Driven by ads. This is not a new concept: TV and radio have relied on commercials since their earliest days. Because, let's face it, something has to pay for all the free programming and services.

Of course, there are ways that users can quell the seemingly endless stream of buttons, banners, video interstitials and more. All you need is an ad blocker: a browser plug-in designed to filter out those unwanted distractions and interruptions.

For many users, though, there's another concern that is more important than simple annoyance: privacy. Some sites do more than just plaster their content with digital billboards. They log your visits (usually via IP addresses) and even track your movements to other destinations. Although the driving motivator is usually just broad-based data-gathering, it can be unsettling to realize you're being followed online.

In response, some plug-ins go beyond mere filtering, promising full-on privacy protection against cookies, trackers, third-party scripts and widgets, and other unwanted invasions.

In this roundup I chose six products: AdBlock, Adblock Plus, Disconnect, DoNotTrackMe, Ghostery and Privacy Badger. There are dozens of other, similar, tools, but these represent a good cross-section of what's available. They're also among the most popular picks in the Chrome and Firefox extensions libraries.

While a few of these plug-ins have companion apps designed to extend protection to mobile devices, for purposes of this roundup I focused on desktop browsers. I concentrated on two browsers, Internet Explorer and Google Chrome, which have a combined market share of nearly 80%, according to Netmarketshare.

I installed one plug-in at a time, then visited a wide range of sites -- including, but not limited to, Crackle, Facebook, Giveaway of the Day, Huffington Post, Hulu, TMZ, Tucows Downloads and YouTube. These sites represent both mainstream and lesser-known destinations -- some notoriously ad-heavy, others focused expressly on video or downloads. Certainly different sites will be affected differently by different ad-blockers, but overall I got a good picture of what day-to-day browsing looks like with each one.

I looked at these sites with each plug-in toggled on, then again with it toggled off. The idea was to make sure none of them were overzealous in filtering, messing with either the content or page layout.

What about speed? In theory, ad blockers and privacy filters should make pages appear faster, as they cut down the amount of content that needs to load. However, this can be difficult to gauge in real-world testing, as there are so many variables that determine how quickly a Web page appears. And if the difference boils down to just a half-second or so, does that really matter? In any case, I looked for any major anomalies, such as pages that were especially fast or especially slow with or without a particular plug-in running.

A few considerations

Keep in mind that a blocker may not always be able to distinguish invasive Web elements from benign ones. For example, some can prevent social-media buttons from appearing, thus thwarting your attempts to "like" or tweet about something.

There's one other consideration, and that's the funding behind the blocker. While most of the apps that I looked at are free or open-source, supported exclusively by donations, at least one, DoNotTrackMe, employs a freemium model (charging a subscription fee if you want advanced features), while Ghostery asks you to provide usage data. Of the six tools reviewed here, only Adblock Plus has an "acceptable ads" feature that allows advertising from Google and other paying companies, and it's turned on by default. But you can easily disable it if you want a totally ad-free experience.

Speaking of which, it's one thing to protect your privacy, but should you really turn off the ads that pay for so much good online stuff? It's food for thought, and if you want a big-picture discussion of ad-blockers and how they may or may not impact the Web as a whole, you may want to read Robert Mitchell's Ad blockers: A solution or a problem?.

Price: Free; accepts user contributions

Compatible with: Chrome, Firefox, Opera, Safari

Not to be confused with Adblock Plus (which originated as a Firefox extension), AdBlock currently works with Chrome, Safari, Firefox and Opera browsers.

Rick Broida AdBlock offers some useful toggles from its toolbar pull-down menu.

What it does: Blocks ads, of course. With AdBlock running, you shouldn't encounter any banners, pop-ups or video ads. However, the plug-in makes no claim to prevent tracking.

How it performed: Because AdBlock isn't compatible with Internet Explorer, I confined my testing to Chrome. The tool offers some useful toggles from its toolbar pull-down menu, including options to pause the plug-in, disable it for just the current page or disable it for the entire domain. This last could come in handy if you discovered a compatibility issue with, say, a site's comment system. I never encountered any such issues.

Rather, AdBlock worked exactly as advertised, keeping ads at bay virtually everywhere I went. It made for a blissfully ad-free viewing experience at Crackle and YouTube. Hulu actually detected the presence of AdBlock and flashed a message asking me to enable ads for the site. After about 30 seconds, however, the message disappeared and the show began playing. So while I didn't have to actually watch the commercial, I didn't enjoy uninterrupted viewing.

Also, AdBlock tallied just five blocked items at TMZ.com, while Adblock Plus counted 14. Why the difference? It's tough to say, because neither program indicates exactly what's been filtered. The only visible difference was that, while AdBlock reformatted the page content to compensate for eliminated ads, Adblock Plus left a few empty spaces.

Bottom line: If you want a mostly ad-free online experience, this does the trick. But AdBlock isn't quite as privacy-minded as Adblock Plus, and Internet Explorer users will have to look elsewhere.

Price: Free; accepts user contributions

Compatible with: Chrome, Firefox, Internet Explorer, Opera, Safari

Don't let the name fool you; Adblock Plus is not a "pro" version of AdBlock. Rather, it's a very similar tool that just happens to have a very similar name. (In fact, the former predates the latter by a few years.) It's somewhat controversial because it accepts money from some large companies to allow their advertising through as part of its "acceptable ads" policy.

Rick Broida Adblock Plus (commonly known as ABP) eliminates banners, pop-ups and videos from the sites you visit.

What it does: Adblock Plus (commonly known as ABP) eliminates banners, pop-ups and videos from the sites you visit. It also disables tracking, though not by default.

How it performed: It's easy to understand ABP's popularity, as it performed extremely well on virtually every site I visited. However, though slightly prettier than AdBlock (at least when you pull up its action menu), ABP lacks a couple of the handy tools found in its competitor. For example, you can't fully disable ABP without venturing into the settings, while AdBlock lets you "pause" it with a simple click.

ABP effectively filtered the ads from the videos I played at Crackle and YouTube, but when I tried to stream an episode of "Party Down" from Hulu, ABP left me staring at a blank window. No ads played, but neither did the episode. After a refresh, it played the episode -- but didn't filter out the ads.

It's curious that one of ABP's most highly touted capabilities, tracking protection, must be enabled manually. In fact, it was only by accident that I discovered it wasn't active: A link on the Features page directed me to the options screen where you add the protection.

Bottom line: Though perhaps not the best add-on with "Adblock" in its name, ABP is definitely the best choice for Internet Explorer users. It keeps ads and commercials away, and optionally stops trackers as well.

Price: Free; accepts user contributions

Compatible with: Chrome, Firefox, Opera, Safari

Disconnect aims to keep you in control of your personal info and does so primarily by blocking all tracking requests. It has the slick design of a commercial product -- and in fact comes from a commercial software developer -- but relies on a pay-what-you-want model (and lets you portion your contribution to charity if you wish). The developer also offers apps for Android and iOS.

Rick Broida Disconnect's visualization view shows a nifty interactive graph of the relationships between the current site and the various trackers.

What it does: Though positioned as a privacy tool, Disconnect also blocks ads. But it won't do anything about the commercials that appear in, say, YouTube videos.

How it performed: Once installed, Disconnect treats you to a treasure-trove of information via its drop-down window. For any given page you visit, you get a summary of all the advertising, analytic, social and content requests made (and blocked) while it loads. For each of the categories you can click to reveal a list of the actual companies or sites that made those requests. It's informative and interesting, to say the least, but probably superfluous for most users.

Likewise, Disconnect's visualization view shows a nifty interactive graph of the relationships between the current site and the various trackers. It's neat, but not something you're likely to use (or need) often. Of greater use, the status window shows how much time and bandwidth you've saved by using Disconnect.

Instead of an on-off toggle, Disconnect gives you the option of "whitelisting" the site you're currently viewing, effectively permitting all the ads and other stuff -- though it still keeps a running tally of all those items, which is cool. Also, you can manually allow individual sites and services, assuming you'd want to for some reason.

Bottom line: Disconnect insulates you from pretty much every site except the one you're viewing and filters out ads to boot. Even if you never bother with its pretty interface, you can take comfort knowing it's working behind the scenes.

Price: Free for basic version; $5/month for Premium version

Compatible with: Chrome, Firefox, Internet Explorer, Opera, Safari

The only straight-up commercial product in the group, DoNotTrackMe (DNTM) takes a freemium approach to privacy: You get the basic anti-tracking features for free, while a more robust Premium subscription, which adds features such as password management, costs $5 monthly. The developer also offers apps for Android and iOS.

Rick Broida DoNotTrackMe not only blocks ads and trackers, but also provides basic password management and disposable email addresses, phone numbers and credit card numbers.

What it does: DoNotTrackMe's name undersells its capabilities, as this plug-in not only blocks ads and trackers, but also provides basic password management and aliases (or "masks") for email addresses, phone numbers and credit card numbers. (These last two options require DNTM Premium.)

How it performed: More features can mean more complexity, and DNTM has the steepest learning curve of any of the tools in the group. But it's worth the effort.

For starters, you must register for an account, even for something as basic as accessing the status menu in your browser's toolbar. Once you do, you're presented with four basic options: Accounts (the password/auto log-in manager), Wallet (storage of credit/debit card info), Masking (creation of aliases of personal info) and Tracking (or, rather, tracker blocking). This last is obvious enough, but the other features require a bit of exploring -- and probably some visits to the online help guides.

If all you want is the tracking and ad blocking, DNTM works well enough behind the scenes. Once you click through to the Tracking area of the options window, you'll see a list of the trackers blocked for that site -- with the option to turn off blocking for individual trackers or the entire site.

Then there's a link to the Tracking Dashboard, which opens in a new tab and shows a graph with the total number of trackers blocked over the past 10 days. Interesting info, but I feel that it should have been integrated into the tool rather than requiring a visit to a whole new tab.

I briefly tested the other features, such as password management, and they worked as advertised.

Bottom line: Though a capable ad- and tracker-blocker with some nice extras, DoNotTrackMe feels unnecessarily complex. Even so, the credit-card alias option makes a strong case for subscribing to Premium.