Adblock is an optional plug-in feature for Firefox users who don’t want to see online ads. However, because of that technology websites may lose advertising revenue. Yahoo! Mail seems to have figured out a way to defeat Adblock. I noticed that lately whenever I want to send an email in Y! Mail, it waits until the large ad unit is loaded before it finalizes the delivery of the mail. If for some reason the ads is not successfully loaded, you’ll get an error message that your mail has not been delivered.
This tactic is similar to other advertising websites where an intermediate advertising step must be completed before the process user is engaged in can continue. For example you must view a short video ad clip before the online streaming TV show can move on to the next segment; or before your search results can display, you must click or skip a page dedicated to advertising. While slower and annoying to some users, this tactic proved to be very effective in advertising as for that moment the ad gets people’s attention like a car crash right in front of your eyes.
Once again, Internet proves nothing is really for free. Well, for now Wikipedia and Craigslist still are, but for how long.