Here's my experience experimenting with several blogs - An inital push on SEO and blog marketing - come up with good tags, post your blog to technorati, make comments on other related blogs, maybe some an article on one of the article marketing sites mentioning your blog, etc - can really pay off, even long term. I have a blog I did as an experiment with this that years later is still getting good hits even though I don't write anything. But ongoing SEO & marketing doesn't pay off as much as putting that time into your topic (including commenting on related blogs).