Since people will only download one of the formats, it's hardly a big deal to host a few extra kb is it? Another huge fuss over something that doesn't need it.
5 seconds work to add an extension in the settings and an okay-dokey - maybe another 5 seconds of typing. You could have spread a little happiness for 10 seconds work and a few extra kb of free space, but instead we get a lot of negative nonsense about how we're somehow sucking the life from DF.org by making our downloads more accessible. Irony, it seems, is not dead.
WE only have 80GB to our disposal.
Sum: Linux + CVS + website + mailinglists + personal stuff
7z would be nice but it also full of bugs. I 7z'ed occasionally and always found a hard time to decompress it.
Several compression tools use different 7z compressions which makes the "smaller" download useless and therefore you download a bz2 version.
bz2 + 7z is always more bandwith then a single bz2 :p
Oh and who is going to provide support to all 7z downloads that fail to extract?
Server specs (Server OS / Apache / MySQL / PHP / DragonflyCMS):
Fedora 25 / Apache 2.4.27 / MariaDB 10.1.26 / PHP 7.1.10 / Mercurial
If the format doesn't actually work, then that is a different argument. No point in having it if it won't decompress, but maybe if a developer wants to support it as a download from his own site it would be nice to be able to add a mirror to it from his download here.
Personally I only make zip version since my stuff is very small and this format will (almost certainly) work. Sometimes I will take the .gz version if offered the choice for a large download file, but I never take anything else unless it is the only option since I am always suspicious that it won't work, or I need some dodgy tool to decompress it.