The site explains its full criteria here, and points out that the list does not include blogs which are part of larger companies “because the traffic of these properties is almost never broken out,” or blogs that do not have revenue (i.e. The Daily Beast “does not take advertising or sell products. In theory, it has little if any economic value at all.”).
That said, the top five are as follows: Gawker, HuffPo, Drudge, Perez Hilton, Sugar Inc. The recently much-talked-about Politico clocks in at number 10. The site had this to say about Gawker:
Gawker Properties. This blog company has a number of successful sites including Gawker, Defamer, Jezebel, Gizmodo, Lifehacker, and Jalopnik. In combination, the sites have about 23 million unique visitors and over 200 million pageviews a month. The companyâ€™s owner, Nick Denton, says the firmâ€™s advertising is holding up this quarter. Traffic at most of the sites is still growing, in some cases at a rate of over 50%. The average CPM for each page across all of the properties is estimated at $15. That makes Gawker at $36 million business. Based on staffing levels, the company should have margins well above 50%. With an 8x operating income valuation, the company is worth $170 million.