Storage space 'absorbed'

Question

Until recently, my available storage space was 86GB. While using the internet an hour ago, downloading apps (Seashore and Chocoflop, both lightweight), i noticed that the available storage space number was ticking down, slowly, by .00 GB at a time. It read 38GB by the time i'd seen it, but there was no apparent cause for the rapid decrease (only safari was open).
In fear of greater damage, i turned the machine off and flitted around here searching for a similar case. Couldn't find one. Finally turned the G5 back on, and found that the number remained the same, that is until it started 'counting down' again! It reached approx. 31GB when it stopped, coinciding with my deletion of some unused apps. It then jumped to 65.5GB, and has sat there since.
No longer /really/ urgent, but there's a solid 33GB of space missing. And that's a concern for me.
thanks in advance to anyone who can offer a possible solution for the sudden jumps.

Answer 1

Couple of ideas:
1) Run Utilities > Console and check your error logs; there might be a repeating error or warning message that is filling up log files.
2) Download a system maintenance utility like Yasu, and have it clear your log, cache, and temp files. There are many maint utilities out there, but I like Yasu because it won't let you shoot yourself in the foot as easily as some other "more powerful" ones.
http://jimmitchell.org/projects/yasu/
3) Tell your browser to clear its caches.
Of course, the shrinkage in free space could be due to some other factor you haven't mentioned: for example, running a bittorrent.
A somewhat longer shot: run Utilities > DiskUtility. Click on the factory name of you hard drive (at the top of the left panel) and check the S.M.A.R.T status at the bottom of the window. It should say "Verified". If not, your harddrive is about to fail.