Blogging was my entry point to writing. It's useful to see what kind of content people are interested in. Plus they say that you need to write some 100,000 words before you're half decent at grammar, sentence structure, style, tone, etc. and blog writing is a fairly safe way to get the hang of it.
Sometimes I'll read my old blog posts and laugh at how bad they are, but that's ok. I'm a better writer now as a result.