Google’s Blogger remained atop the blog site rankings with 37.2 mln unique visitors, up from 23.6 mln in February 2007 – or a growth of 58%, according to Nielsen Online. WordPress was up an impressive 209% YTY, increasing its unique audience to 16.5 mln. Fifth-place TheHuffingtonPost.com’s growth was also impressive: Its unique audience grew from 1.1 mln in Feb. ’07 to more than 3.7 mln – or 241%.