|Don't ask to ask, just ask|
The real question here is "who listens to TIOBE?". Do any of us know? I don't. If people are listening to TIOBE, it really doesn't matter if we disapprove of the methodology and can show how it disagrees with Google's own rankings. It will bite us, unless we are proactive. Of course, if no one is listening, then TIOBE's rankings don't matter at all.
TIOBE is claiming that they can predict which languages are a good investment. Which languages will you be able to build your career around five years out? Which languages will you be able to build teams around not just today but five years hence when you have five versions of your project in maintenance mode? Do we really want college students and managers thinking they are jeopardizing their careers by investing in Perl? If they trust TIOBE, that is what they will think.
Perl's success of course depends on the quality of the language and the quality of developers attracted to it. This in marketing terms is an "order qualifier": the thing that even lets us make the Perl pitch. But to actually make the sale we need more than a good language and a good community: we need managerial mind share and new blood - neither of which we will get if we simply dismiss those like TIOBE who, however awful their methodology, view those very managers and students as their target audience.
TIOBE may or may not be important, but TIOBE rankings raise issues of deep importance. Moritz is right - this isn't the death of Perl, but it isn't exactly a PR success story either.
So what can we do?
In reply to Re: Perl is sinking (TIOBE): all time low for Perl