You can find my WordPress hosting article here, because of an experiment the comments for that article are here, while the article itself is "on it's own".

It keeps amazing me that I keep seeing people use robots.txt files to prevent sites from being indexed and thus showing up in the search engines. You know why it keeps amazing me? Because robots.txt doesn't actually do the latter, even though it does prevent your site from being indexed.
Let's go through some terms here:
Indexed [...]

I recently changed the permalink structure of this Wordpress blog, going from /%year%/%monthnum%/%day%/%postname%/ (Wordpress default i think) to the much more elegant and simple /%postname%/. This is very cool ofcourse, both because it's simpler and SEO wise, but on an existing blog, this leaves you with lots of links that point to the wrong URL. [...]