@PitaJ is correct, the option is called the "tags whitelist", and you can decide which tags to allow, and do so on a per-category basis
Latest users widget
Not sure why we haven't added this before but here it goes
Added it to our homepage as well. You can set how many users you want to display in the widget ACP.
Now we just need to add the "What's Going On" widget, and we'll be back to the 1990s