Some useful social media statistics:

According to Nielsen Online:

“Facebook swelled to 29.2M unique visitors in the US, up more than 10 percent from May. Meanwhile, professional social networking site LinkedIn grew more than 20 percent month-over-month to 9.5M uniques. Year-over-year, that represents 77% growth for Facebook, and 187% for LinkedIn, respectively.

Meanwhile, it would appear that MySpace has officially hit a plateau in the US, though it still more than doubles up on the competition. Its 59.4M visitors in June represented zero growth over last year, and was a marginal decline from the 60.6M reported by Nielsen in May.

Elsewhere, Ning debuts on the charts with 2.2MM unique visitors, up 326% from last year when the create-your-own-social-network site was just getting off the ground.”