I don't know how effective it is. But, do you all know that there is actually a startup behind this "share this" button? http://sharethis.com/ http://sharethis.

I don't know how effective it is. But, do you all know that there is actually a startup behind this "share this" button? http://sharethis.com/ http://sharethis.com/ And, they are doing quite well too - http://siteanalytics.compete.com/sharethis.com/?metric=uv http://siteanalytics.compete.com/sharethis.com/?metric=uv