Facebook is quickly closing the gap in U.S. usage v. MySpace. Facebook became the largest worldwide social network last April, when they overtook MySpace. MySpace continues to dominate in the U.S., with 75 million monthly visitors (Comscore). A year ago Facebook had just 35 million monthly U.S. visitors, compared to MySpace’s 69 million, meaning MySpace was about twice the size of Facebook in the U.S. Two months ago Facebook had risen to just 40 million users, and MySpace had grown to 75 million, so the ratio was still hovering around 50% (53% to be exact). But in the last two months Facebook has added nearly 10 million monthly U.S. users, surging to 50 million U.S. visitors in November. MySpace has stayed steady, but the Facebook is now 2/3 the size of MySpace in the U.S. If Facebook’s growth rate v. MySpace in the U.S. continues, they’ll overtake them sometime next year.