Had a bit of a problem on one of the office PCs I use for downloading Bittorrent files across the Internet.
Because Bittorrent has a bit of a dodgy reputation (never! -Ed) I use an IP blocking/monitoring package called Peerguardian - basically it blocks any incoming IP calls from companies such as BSkyB and others that want to see what's cooking.
I installed the open source software last summer on my file sharing PC and have left it humming in the background ever since. It blocks around a dozen or so IP calls a minute from a surprising number of major companies and organisations.
Around Christmas time I noticed my hard drive space on this PC was running low, so I pruned more than a few files to free up around 20 GB of the available 120 GB.
Last weekend I got a low HD space warning again. The free space was down to 0.5 GB!
So I investigated. And investigated. It took me a few hours but I finally figured out it was Peerguardian, whose default setting is to log and archive all IP calls - the archive was more than 40 GB big!
Anyways, I've turned off the archive logging function - so if you use Peerguardian and find your HD space disappearing, you'll know why...