Pro tip: set your notification settings to silent by default. I occasionally turn on notifications for our automated system alerting Slack channel, usually when I'm not actually at my computer.
One thing I do think we do as Slack users is rely on it too much as a general information dump: even with the history, stuff gets lost. Slack is no replacement for wikis or other more static information repositories, make sure you extract valuable knowledge out and put it somewhere more suitable (and findable).