This is a simple web proxy written in Perl back in 2001. It does a few things:

• It blocks ads. Lots and lots of ads. If served from 2001-era ad servers.
• It caches images from popular sites like Slashdot. This should be really useful if you visit 2001-era sites, on a 2001-era connection when loading such common images is slow, with a 2001-era web browser which didn't do all that caching itself particularly well.
• It automates some tedious tasks from some online games. With all the above caveats. I actually didn't play online games much in 2001, but someone I knew did.

It's distributed under the same terms as Perl. It might be a useful starting point if you'd like to write your own Perl proxy, in the process of studying historical computer languages or something.