Social networking usage by Americans continues to soar. According to a new report from The Nielsen Company, Americans spent 17% of all their Internet time using social networking sites. This was nearly triple the time spent a year ago.As users spend more time on social networks, advertisers are starting to take notice and move their campaigns to social networking sites. According to Nielsen, the online advertising spending on top social networks and blogs was estimated at $108 million for August 2009, a 119% increase over August 2008 figures.

Check out the chart above, you can see that although online ad spending across all sites is down in many sectors, it is up in every sector for social media sites.

Social networks offer advertisers several key advantages over regular sites. They can target users based on location, age and relationship-status by virtue of having accessible profile information. Companies can also communicate directly with potential customers using social media channels.

Do you spend more time on Twitter and Facebook than you did a year ago? Have you noticed any changes in how you respond to advertisers? Let us know in the comments.

Originally posted on Mashable by Christina Warren on September 25, 2009