Web AIDS comes in different forms. It can be caught in many different ways, unlike IRL AIDS which is only ever gotten in the ass. We will only be discussing Web Aids 2.0 because it's the most important form of Web AIDS. For version 1.0 please consult wikipedia.
Web AIDS Vista
Web AIDS Vista is what you get when you open, for example, a media player and it blows you away with plenty of Ads (Pronounced AIDS). There are various media players that will bombard you with teh Web AIDS, causing you a delay in watching a Thai Ghost Rider rip or exciting porno movie.
The following are the most common and infectious forms of Web AIDS:
Windoze Porno Player
The fact that MediaPlayer immediately infects you with AIDS and Aidsware is mind boggling, given the fact that you (most likely) have purchased your copy of Windows and should not have to look at 50 Cent's vagina or K-Feds "exciting new album." It's extremely annoying when all you want is to open a good movie and it takes you 46 hours to load fucked up HTML and picta's in the player itself.
NSBMC / Microcommodoresoft Explorer superAIDS
If you are also using IExplorer, your AIDS state is highly advanced. Pray for death. You will be unable to view any actual web content without clicking through ten ads telling you about the latest release from Death Cab For Cutie and how you should pay money for gay porn. Of course, all the ads are targeted at America. There is no Europe or Moscow, this is all a lie.
RealPlayer has always been famous for it's extra virulent Web AIDS. Hell, chances are you kindly removed its AIDS from a neighbor's machine who wonders why his superturboextraplus 800 ultrahertz computer suddenly became as slow as his old XT machine with 10 mb harddisk space stackered to 20 mb. People especially enjoy their message center option, which suddenly has 325 popups coming up a day, asking if you would be interested in the new Celine Dion album or the movie Crossroads with Britney Spaers. They also blow a lot of Web AIDS at you whenever you open up a screen. Fortunately when you have a popup blocker it won't show shit. Still, as if by magic, it will take 300 years to load up the screen and in that while not open up your movie, even if you commanded it so a million times. IT... has.... to.... load.... first.
QuickTime is a little more subtle with it's Web AIDS, but its still in there. Luckily there are plenty of extra filters you can install with other media players that will allow you to play Quicktime in them. And totally erasing all it's extra crap from your Windows startup will save the day. Whenever you start up Quicktime on itself will give you full blown Web AIDS. They always seem to have the best and crappiest albums by stars you never ever heard of, such as Gary Flintman sings the blues, or Henry Lee Lucas sings the Christmas classics.
Web AIDS Professional SP2
There is also a fun side to Web AIDS though, which is giving it to someone else for no reason. The general idea being just shouting AIDS in a chat channel, and who ever hears you will now have teh Web AIDS 2.0