And the winner is… the biggest online brands of 2007

Facebook, Wikipedia and online classified site Craigslist were the most successful online brands in the US in 2007, according to a report by online metric company comScore.

Facebook.com’s dramatic rise in profile over the past year paid big dividends, with visitors to the site jumping a big 81% for the year to achieve 34.7 million monthly visitors by December 2007. Wikipedia gained a slightly less impressive 34% but, with 52 million visitors per month using the site by December 2007, it is now entrenched as the web’s most popular reference hub. On the classified side of things, Craigslist picked up traffic by 74% in 2007 to pick up 24.5 million monthly visitors by the end of the year.

An interesting mix of niche websites achieved the fastest growth, many of them moving dramatically off low bases by acquiring complimentary sites. A site called Everyday Health gained 349% after acquiring various health oriented sister sites such as Drugs.com, while women-focused content provider Glam Media grew 213% with several acquisitions.

The website that achieved the fastest visitor growth by organic means belongs to officegoods retailer OfficeMax – it achieved 199% growth thanks to its ElfYourself.com promotion, a feature that allowed visitors to create a Christmas e-card with their faces superimposed on a short dancing elves movie. Go figure.