Indeed this conversation came up recently as we (TPF and the PerlMonks admins) were discussing some things to do with the PerlMonks funds we have. The first and most obvious use was to beef up the hardware to speed things up a bit. I contacted Pair and they very generously spec'd out some new boxes. The PerlMonks admins are currently in the early stages of working on an upgrade.

To answer your other question, yes, Pair donates their hosting and they run an ad on the site. Pair has been absolutely fantastic in this regard. They have given us nice hardware, they keep the site up and running 24x7, and they handle our support requests very quickly.

So for funding, I agree with the others that a PerlMonks donation is unlikely to get used right away. However, if you follow the TPF grants that have been awarded and you support the work we are funding, that money will get used. You can find more on what we've been up to here: TPF 2008 report.