A database is easy to fill and slow to clean. Two settings decide what ends up in yours, and both are cheap to get right now and expensive to unpick a year from now.
This page gathers the articles that settle those decisions. They live in the Setup Guide section of this knowledge base, and cover what to choose and why. The rest of this section covers how to do it.
An article in this knowledge base can only be filed in one section, so the Setup Guide holds them and this page links to them rather than repeating them. You will find them under For administrators, in the Setup Guide, stage 6, Manage.
The how-to articles: mass import, bulk actions, assigning profile tags, archiving, searching and exporting. Read the decision articles above first if you are setting up for the first time, then come back here.