Even with the best organization (old content deleted), I don't want to wade through the conversations about it or all the other noise. Chat is temporal, the discussion about something like "should x be updated" is immediately irrelevant after the decision is made.
Slack search for <insert error name here> is high-value in historical context that's tough to replicate elsewhere. All at once, you learn if anyone's ever asked about the error before, and if so, see the conversation on resolution.
Email is far worse, in fact, because:
* Everyone has a unique view
* Unless there are lots of cc-everyone style emails, you might not even have anything to find. (And cc-everyone sucks for 100 other reasons.)
* You can't find anything predating the start of your employment
The biggest issue with searching both chat and email is the absence of a result doesn't help: it's possible it was a private chat, or an email chain that you weren't a part of, but there's no way to tell.
(Side note: A very locked-down wiki isn't any better, but that's a conscious decision rather than default.)
Many companies use Outlook groups. Those are mailing lists.
The important part is we know why a decision was made. Chat logs are not a good archive because there is too much to sort thought that isn't relevant. Better than nothing, but what is really needed is an effort to document why in a place the right people will find it when they need to know.
That said, none of my employers have ever made effective use of this. I don't think open communication is an instinct that most people have.
Chats have the same problem: they aren't searchable by people who weren't in them.
meanwhile https://lkml.org/
Also, even if I am part of the channel, there is no way I can search and locate what I want without knowing the right keyword to search for. Sure, the information is all there, but that only ads to the frustration. Search interfaces in Slack & all are very limited / too broad.
That sounds horrible and very fragile.