Here are the latest numbers of the Top 20 Online Social Networks.

Besides the well-known platforms like MySpace or Facebook there are some important trends and changes happening right now.
Elsewhere in the social networking space, Facebook continued to narrow the gap on MySpace, a trend we also noticed last month. Unique visitors to the site grew to 38.2 million, representing a more than 10% month-over-month increase and a 100% jump year-over-year. MySpace saw 61.3 million unique visitors – up slightly from last month, but still essentially flat compared to the same period last year. And business network LinkedIn grew 146% year-over-year to 10.8 million unique visitors.

Twitter is apparently growing rapidly. According to stats just released from Nielsen Online, Twitter recorded 2.3 million unique visitors in August (US-only), an increase of 422% from the same period last year. Moreover, visitors to Twitter spent 55% more time on the site on average – a total of more than 7 minutes per user. Those numbers point to rather robust growth for the site, especially considering many of its most rabid users access it through a third-party client like Twhirl or Tweetdeck.