Gaining Readership by Joining Niche Social Networking Sites

I came across this post on ProBlogger that highlights a few simple ways to increase your blog circulation and readership by joining niche social networks. Here's a summary of the recommendations posted on the blog.

1. Interact with members of community sites for about 10-15 minutes a day, people will stumble upon and discover your blog.
2. Share your knowledge with smaller more niche social networks and you can be considered a guru quickly.
3. Make sure to fill out your profile in the social networks, and include your blog links there! You will be surprised by steady traffic it can bring to your blog site.
4. Join social news voting sites and forums like Digg and Redditt, research shows that for these sites conversion from visitor to subscriber is high.

These are just a few recommendations to helping improve your blog's readership. What are some other tips that can help boost traffic?