Blogging is a popular method many people use to create their sites as it takes all of the technicalities out of creating a site. Most people use WordPress to create their primary blogs but did you know many bloggers use blogging services to set up sub blogs.
A sub blog is a blog that is part of a larger network and usually offers its users some space on their server and your blog becomes a sub blog of the main network. Many services are very general and allow you to create a blog on any topic.
One trend is towards networks that focus on a single topic. The benefits of this is that the search engines like related content and in essence see this as a large site with lots of fresh content that is added regularly.
If you are new to this idea take a look at destroydebt.com they allow users to set up their own blog. Your new sub blog carries more weight as it is riding on the coat tails of the main site. In this instance the blogs that the users can set up are debt consolidation blogs.
This set up benefits both the main and the sub blogger, one benefiting from fresh content and the other the SEO benefits of being associated with an established site. Many similar systems, Destroy Debt included also allows you to earn revenue from your sub blog.
The benefits to you are that your blog is more likely to rank higher being part of a larger site than you would setting up a new blog from scratch. You can expect to see more of these community type blogging on specific topics in the future.