The information presented here is based on the traffic rankings on Alexa.
Yahoo or Google?
Despite being omnipresent enough to become a verb in our present society (you never tell someone to “Yahoo” something when they want information on it), Yahoo is still more popular than Google and is in fact the most popular website on the internet. This seems very surprising but keep in mind Yahoo offers other features like online games that might explain the difference in traffic.
Facebook or MySpace?
MySpace, despite being maligned by so many people, is the 5th most popular website on the internet, barely edging out Facebook which is 6th.
Wikipedia or YouTube?
This one is no contest. Wikipedia is the 9th most popular website, YouTube is the 2nd.
Blogger or LiveJournal?
Another one that isn't even close: Blogger is the 12th most popular website, LiveJournal is the 69th.
Flickr, Photobucket, Fotolog, or ImageShack?
This one was very surprising to me! I've never heard of it, but Fotolog is by far the most popular. ImageShack is 34th, Flickr is 39th, Photobucket is 30th, while Fotolog is 13th.
RapidShare or MegaUpload?
When it comes to sharing files online, Rapidshare has a slight edge at 13th versus MegaUpload's 14th.
Mininova or The Pirate Bay?
The Pirate Bay is one of the most popular sites for Bittorrent tracking, but it ranks in at 128th, well behind Mininova's ranking of 53rd.
Adult Friendfinder or CraigsList?
As you might expect, Craigslist has the edge here, but what might surprise you is that the margin is quite small. Craigslist sits ranked 66th while Adult Friendfinder is 68th. The two websites are separated only by Google's Slovakian portal.