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The New York Times ran an interesting story today about ad blocking software for web browsers.

I’ve used variations of ad blocking over the last few years, in an effort to speed up my Internet browsing. After all, every ad on a web page takes time to download. Some ads use Flash or Java to provide animation, and those ads can take additional time for a browser to download, process and present.

AdBlock Plus, which is discussed in the Times, is one of the easier tools to use, but it only works in Firefox, my favorite web browser.

Updated 8 September 2007: AdBlock Plus supports several third-party lists of domain names – see this page for details. Subscribing to a list such as EasyList or EasyElement is a quick way to set up a comprehensive ad blocking system in Firefox.

There are other tools available for Internet Explorer, but I won’t discuss them here.

In the past, I’ve used a more comprehensive approach that blocks ads from appearing on a computer or a network. This method uses a hosts file, as described in this Lifehacker post and in this page, to block well-known ad servers, based on their domain names. This isn’t a good idea unless you own your computer and you understand what you’re doing. I wouldn’t do this on a corporate or public computer.

Updated 8 September 2007: Yoyo.org has a page with detailed information about ad blocking at the router and computer level.

It’s also possible to do this with an OpenDNS account. Just add the domains that the router or your computer should block. I mentioned OpenDNS on July 13.

Ad blocking is easy to do

For both the hosts and DNS methods, the strategy is simple. I’m trying to stop my router or computer from looking up the ad servers, thus blocking the ads themselves. Usually I’ll see a blank space or a 404 (file not found) message in place of the ad. In the example below, OpenDNS has blocked an ad server before my browser could open the ad.

Some of my readers may have noticed that I do include Google Ads on this web site. The Google Ads are located at the bottom of each page, and Google tries to select appropriate ads based on my site’s content.

Last week, I also added some dynamic ads from Amazon.com that show prices for my courses’ textbooks. Here’s an example.

I’m hosting these ads to see how the systems work before I include ads on some of my customers’ web sites. I do receive a small amount of cash if anyone clicks on the ads, somewhere between 5¢ and US$1, so this really isn’t a revenue stream for me.

Updated 8 September 2007: To my chagrin, I noticed that the default settings in AdBlock Plus will block my Amazon ads. It’s easy to fix this by deactivating or removing the entry for rcm.amazon.com.

But ad blocking can affect the revenue streams of some web sites, especially if a significant number of users are blocking ads. A few small web sites are throwing the baby out with the bathwater by blocking Firefox users, usually redirecting them to whyfirefoxisblocked.com, based on the ridiculous assumption that every Firefox user has also installed and is using AdBlock.

This kind of filtering by a web server isn’t an invasion of privacy. It’s trivial work for a web server to determine the kind of browser that a user is running, because the browser itself includes that information whenever it requests a file from a web server.

Blocking Firefox is not an option for larger web sites

While Internet Explorer still holds the most market share, a significant number of users, including myself, usually use Firefox for their web browsing. No sane advertiser wants to block users who are smart enough to install and run an alternative browser, as smart users might have more disposable income or more influence on their company spending.

There are some ways to circumvent ad blocking. Most ads come from third-party web servers. Webmasters can choose to server the ads themselves. Anyone who wants to see the site will have to see the ads, because these users won’t want to block the web site itself.

As the Times mentions, Microsoft itself is caught in the middle of this problem. Microsoft doesn’t include ad blocking software in Internet Explorer, but the company hasn’t prevented users from loading that software, either. But Microsoft also has a significant revenue stream from ads that its MSN sells.

HPU students can check the front page of Pipeline to see a list of changed and canceled classes. This is a good example of a pull system. Students have to log in to Pipeline and look at the channel to see the information.

Here’s a screen shot of today’s notices. There are no classes scheduled today, of course, because it’s Labor Day. The fall term starts tomorrow.

The channel only reports official changes, though. In the past, the university posted these changes by the classroom door, using a paper sign. If an instructor hasn’t told the university that they are canceling a class for a specific day, the change won’t appear by the door or on this new list.

It would be nice if this list were available on the public web site or an RSS feed. As I mentioned on April 16, a push system could send out notices to the affected students, perhaps by email, text messages.

RSS can be either a push or pull system, depending on how it’s used. For example, users can have the posts in this blog sent or pushed to them by email. Just pull up the RSS feed as a web page and look for the option.

Most users tend to employ RSS as a pull system. It’s a bit different from web browsing, as an RSS reader can be set to automatically check and retrieve new articles on a schedule.

I have a longer discussion about RSS and how students can use it in my courses – it was posted January 23, and it links to an older post from September 23, 2006.