Time on social media is eating into time spent on other online activities (eg. instant messaging, portal sites, email).

According to comScore’s US report ‘The State of Social Networks as a Media Platform’, the top 20% of social media users visit social media sites 2.4 times per day and spend 31 minutes in these spaces. This is twice as long as the same users spend on instant messaging and email.

The report indicates that this is good news for advertisers, as exposure to online advertising is high and climbing. The report found that for July 2009 more than one-fifth of online display advertising impressions occurred on social media websites.

Despite these findings, the report said just 3.5% of the US’s total display ad spend went to social media sites. The lion’s share of this figure is divided between MySpace and Facebook, with MySpace receiving 1.4% and Facebook 1.5%. As for impressions, MySpace came in at 9.2% and Facebook at 8.2%.