4 quick ways to make your blog more social
1- Social Links: Make it easier for your readers to share and recommend your blog to their friends and contacts. ShareThis lets you share in many ways: by mail, twitter, facebook, etc..
2- Polls: Polls are an excellent way to start discussions and get some links to your blog. If your blog uses WordPress, check WP-Polls and there are also many services like PollDaddy that create and share polls on many platforms.
3- Rating: A good way to get feedback from your readers by allowing them to rate your articles. Analyzing this data will help you find out what kind of articles your readers like the most. For WordPress users I recommend GD Star Rating.
4- Social comments: The reality is that many of the discussions relevant to your articles take place in social networks, with Disqus your readers can comment on your blog through twitter and Facebook.