No, really guys, if you can stand it, blog. If you do not have any better way to waste your time, blog. If you do not mind virtually no one reads your weekly babbling, blog.
Sure you can find more blog posts about PHP. It's being used by lots of people that can get excited easily by something we all take for granted for years. It's being used by people that are not programmers (neither by profession nor inclination) and just happened to need to do something and now are ecstatic that they succeeded and quite often thanks to their profession they can write. You can find more blog posts about Ruby, since it's still fairly new and doesn't have the community tools and sites so well set up. Sure you can find less blog posts about Perl if most of the stuff that'd end up as a blog post in other communities gets uploaded to a central site (yes, CPAN) without any fuss or gets posted here.
If you do not have a better place to put things, you blog. And you end up searching high and low for a snippet of code or a library.