Following up on this week’s post detailing Facebook growth, new stats for June from Compete show three significant trends among the major social media sites.

• Facebook is making a big run at Google in number of unique visitors. Facebook now has 122.6 million unique visitors, with a year-over-year growth rate of 248.17%, compared to Google’s 145.9 million uniques and 7.45% growth rate
• Twitter had strong growth in June after a flat May, with a 16.57% growth in unique visits and a 12.05% growth in overall visits.
• Plurk lost 11.48% in uniques and 12.68% in overall visits in June.

Other interesting stats: While Friendfeed lost only .26% in unique visitors, it dropped 20.26% in overall visits. MySpace, while far behind Facebook with nearly 61 million uniques, still had 7.19% growth last month.

What does this mean? My take: Obviously, the Facebook-Google wars will only escalate. Twitter, at No. 3 behind Facebook and MySpace, is not peaking as some suggested after the May numbers. And it increasingly appears people see Twitter and not Plurk as their micro-blogging tool of choice.