Each of the Wordpress plugins listed below will encourage visitors to join the conversation on your blog. Conversations are the first step to building a strong blog community. They also encourage repeat traffic as people want to be a part of the ongoing discussion. As the conversation and your blog's community grow, so will your blog's traffic!
1. CommentLuv
Adding the CommentLuv Wordpress plugin to your blog is a great way to show your readers that you value them and the comments they leave on your blog posts. With CommentLuv, every comment left on your blog automatically includes a snippet and link back to the commenter's most recent blog post (assuming the identifying information in their submitted comment form tracks back to a blog with a feed from which the most recent blog post can be scraped). Bloggers love this Wordpress plugin because it can increase traffic to their own blogs more so than a traditional comment link from their names can.2. Show Top Commentators
Most people are inherently competitive and like recognition. The Show Top Commentators Wordpress plug-in leverages both of those innate desires by recognizing and rewarding the most vocal people in your blog's community. Using the Show Top Commentators plugin, you can create an automated list (which you can reset on a daily, weekly or monthly basis) that displays a list of people who are the most frequent commentators on your blog. The list includes a Google-friendly link back to each commenter's blog or website. A word of caution, many users report an increase in spam comments when using the Show Top Commentators Wordpress plugin. However, the plugin does include settings to help you filter out spam comments.3. Subscribe to Comments
Read the review. The Subscribe to Comments Wordpress plugin is a must have for any blogger looking to increase comments on his or her blog. With this plugin, your blog readers can subscribe to receive email alerts when new comments are left on posts they're interested in. It's a great way to draw people back into a conversation that they've already expressed interest in.

