The 3 billionth photo was uploaded to Flickr yesterday, the company said on its blog.

The site has grown just over 50% in 2008 — it was one year ago that the 2 billionth photo was uploaded.

Facebook, however, is still the biggest photo-sharing site on the web, with over  billion photos stored on the site. Photobucket is second, with 6.2 billion photos.

Flickr may not be the largest photo sharing site in the world, but it's among the smartest acquisitions made during the Web 2.0 era, writes Mashable. Yahoo bought the site for $35 million in early 2005.

Last April Yahoo made good on its promise to add video sharing for Flickr Pro members, which pay an annual $25 subscription fee. Videos are limited to 90 seconds and are positioned as "long photos," so as to avoid the perception of competitive rivalry between itself and sites like YouTube.

In a casual July poll, social media blog The Social Path asked readers what online services they pay for or would be willing to pay for. The majority of respondents cited Flickr Pro.