Well, using a forum search function is really painful. It can be hard to find old posts - even if you know
that you have read (or written) that post some months ago. Forums are great for discussing new findings, but they don't work well to preserve those findings.
Wikis can be really more structured, and they can focus on actual information (without the brainstorming stuff (and completely offtopic posts) being scattered into various similar threads that you have in forum discussions). In general, a wiki could
be nice. But I don't know how much work it would be to host it (and if anybody would fill it with useful info).
The Amstrad CPC did have a nice wiki, http://cpcwiki.eu/
(can be still accessed via wayback machine in case it doesn't accept your browser), it's covering games, hardware, software, pcbs, magazines, adverts, expansions, schematics, with photos, scans, screenshots, and pretty much everything - but that's some sort of an exception, I haven't seen anything similar for other computers/consoles yet (unfortunately).