I noticed that Abandonia still generally uses .zip archives for all of the downloads. I, personally, started using 7-Zip several months ago. It's an open source compression program which supports every major format, at least every one that I know of, and it has very high compression.
The best compression results I get are obtained using the .7z format, on ultra compression, using the LZMA method, with a dictionary size of 128MB, a word size of 273, and a solid archive setting. With those settings I get around 20% better compression, sometimes more, sometimes less, than the maximum I can get with WinZip.
For maximum compression you need 2GB of RAM though, but the results are usually very impressive. The compression times are longer, of course, but that's not really a big deal. 7-Zip also has multi-threading support, and a lot of other features.
So, I think Abandonia should recompress all of the archives to 7z format. The site could significantly reduce bandwidth by doing that. It would take a little while, but it would be worth it.
Occasionally I have an archive that compresses better with .zip format than it does with .7z, but the good thing about 7-Zip is it supports compression with all the major formats, as well as for decompression.
So, what does everyone think? It could save a lot of money, hopefully. :wondering: