CNET has posted their list of Top 10 Web fads. I guess I've been under a rock because I didn't know about mahir's site, but all 10 have been discussed in these forums over the last couple of years. Just for fun, I did searches in the forums to look for the oldest post that mentions the fad or a thread dedicated to the topic.
1. Hampsterdance (MacRumors mention)
2. Mahir (MacRumors mention)
3. All your Base are Belong to Us (MacRumors thread)
4. Dancing Baby (MacRumors mention)
5. Hot or Not (MacRumors mention)
6. Friendster (MacRumors thread)
7. Ellen Feiss (MacRumors thread)
8. Star Wars Kid (MacRumors thread)
9. Blogger (MacRumors mention)
10. JibJab (MacRumors thread)
What important fads did they miss?2. Mahir (MacRumors mention)
3. All your Base are Belong to Us (MacRumors thread)
4. Dancing Baby (MacRumors mention)
5. Hot or Not (MacRumors mention)
6. Friendster (MacRumors thread)
7. Ellen Feiss (MacRumors thread)
8. Star Wars Kid (MacRumors thread)
9. Blogger (MacRumors mention)
10. JibJab (MacRumors thread)