Would that cause problems if people, for example, click a link in an old email (that is for an archive campaign)?Every time when an email is sent, a log is stored in that table. The table is also used to cross reference the subscribers that have received emails vs the one that didn't, so that the app knows and not send same email multiple times to a single subscriber.
If you delete the archive table, you'll lose the delivery logs for archived campaigns, which should be fine for most people anyway..
Great. So the only thing NOT having the archive campaign is I wont be able to see how many users were sent emails for old campaigns. I won't lose things like open / clicks stats?Nope, it will be fine.