Facebook.com reaped the benefits of opening registration to all users, jumping 81% versus December 2006 to 34.7 mln visitors in December 2007, according to comScore. Wikipedia Sites gained 34% to reach nearly 52 mln visitors, continuing its reign as the Web’s most popular reference hub. Leading classified site Craigslist.org jumped 74% to 24.5 mln visitors, while AT&T grew 27% to 30.2 mln visitors boosted by its exclusive deal with Apple as carrier for the iPhone. Yellow Book Network jumped an impressive 137% to 10.4 mln visitors
| Fast-growing site | December 2006 | December 2007 | Growth, YTY |
| Total US Internet Audience | 174,199 | 183,619 | 5 |
| Everyday Health | 2,690 | 12,073 | 349 |
| Glam Media | 7,994 | 25,028 | 213 |
| OfficeMax | 5,130 | 15,339 | 199 |
| Demand Media | 5,999 | 14,958 | 149 |
| Yellow Book Network | 4,386 | 10,388 | 137 |
| ValueClick | 6,339 | 13,013 | 105 |
| Facebook.com | 19,105 | 34,658 | 81 |
| WorldNow – ABC Owned Sites | 8,714 | 15,474 | 78 |
| Craigslist.org | 14,075 | 24,468 | 74 |
| Experian Interactive | 8,054 | 12,500 | 55 |
| Yellowpages.com Network | 16,168 | 24,453 | 51 |
| AmericanGreetings Property | 11,982 | 18,102 | 51 |
| Comcast Corporation | 18,716 | 26,445 | 41 |
| UGO | 8,450 | 11,912 | 41 |
| The Mozilla Organization | 10,948 | 15,267 | 39 |
| Answers.com Sites | 10,707 | 14,899 | 39 |
| Wikipedia Sites | 38,585 | 51,851 | 34 |
| iVillage.com | 13,545 | 17,234 | 27 |
| AT&T | 23,833 | 30,212 | 27 |
| Internet Broadcasting Systems | 9,894 | 12,394 | 25 |