Blogs represent a whole new way for art, ideas, and information to become popular. Most blogs are just for the person blogging. Many more are for the blogger, plus there friends and family. Some blogs are of interest to a wider public, and the nature of a blog allows a much more interesting relationship to develop between the writer and his or her audience than was possible in traditional print media. Blogs are also interesting because it allows for the growth of a community of writers and artists to grow and interact with each other.

What does this mean for promoting artists and ideas? Blogs fit into the larger picture of digital media in many ways. For one, search engines and blog-aware services like del.icio,us are aware of what sites are getting linked to the most in both static sites and blogs. By having your own blog, and commenting on people and things that are important to you, you help those people and things become more popular in all these arenas (as long as you know the basics of SEO optomized linking, that is). The more you comment on the things you like, and the more people who read your blog and care what you have to say, then the more you help promote those people and ideas.
All of this represents a much more democratic means of information filtering than traditional media, where editors, businesses, governments, and other parties decide what stories are published.  When you link to web pages, you're kind of voting for them.

If nothing else, blogging can be a fun way to stay in touch with friends and family, and to keep a great personal diary of your adventures and photos. Try it! And remember that whenever you're posting about something, you're helping it become more successful.