I was at a meeting recently where this discussion came up.
Search Engine Optimisation(SEO), if you have not come across it before, is the process of writing copy so that keywords can be picked up by the search engines when they look at your site. The aim is to get a better ranking in the search.
Whilst this can be of some use with regard to the static pages on a website(search algorithms are constantly changing), in my opinion it can be a bad idea for a blog.
A blog should be the personal writings of the poster and when read you should be able to discern their individual style. Ensuring that a post is clearly written and formatted may assist with search rankings, however having posts specifically rewritten just for the search engines can have a negative impact.
The occasional use of links in a posting can also be a useful addition, however if overdone can actually count against it as the search engines will just think it is intended to generate traffic rather than provide useful information.
How do you prefer to write? If you know anyone currently using SEO for blogs, are they worried about the effect on their style?