PostRank claims to measure social engagement, including blog posts responding to someone else, bookmarking an article, leaving a comment on a blog, or clicking a link to read a news item.
CoveritLive's web based software publishes your commentary in real time like an instant message. One-click publishing lets you add polls, videos, pictures and audio clips instantly, and take questions.
fav.or.it is our answer to the current separation of feed reading and commenting. We have built a web interface that lets you read all your favorite content and at the same time take part in an interactive community.