Not everyone has time to come on DCW ALL THE TIME. Real life takes on a higher priority than a virtual one.
Besides, there are definitely people who will come back after years/months being inactive due to various reasons. They might have lost interest in DC at times, but rekindle their love for DC and come back here again and maybe contribute something.
Also, making an introduction is up to the person, why bother to make such a rule to "force" everyone here to make one? If s/he doesn't want to make one, so be it. You don't really need an introduction to know a person.
I think people in DCW shouldn't worry about taking breaks and worry about whether or not his/her own account will get deleted. (I actually think it will get annoying awhile if you keep thinking whether or not your account in DCW is still here :wink:)