Facebook has overtaken Yahoo to become 3rd largest website on planet earth. This rank is based on number of monthly unique visitors.
According to comScore, approximately 648 million unique visitors visited Facebook in November 2010, compared to 630 million for Yahoo. Both Yahoo & Facebook were dead even with 633 million worldwide unique visitors each for the month of October.
Prior to this, it took Facebook only 18 months to become the 4th largest website. It is also the 2nd largest video and source of videos for other sites in United States. However, Yahoo is still the No. 1 site in terms of monthly visitors in US.
Microsoft is on the 2nd spot with 869 million UVs and the top spot is occupied by Google with 970 million UVs.