I have noticed that when I am taking the time to categorize a series of pages, usually because a new category has been created, that I will in effect StirThePot.
You may have noticed when someone else is cooking that when they stir the pot or open the oven door, that the aromas are released into the air and those not aware of what is on or in the stove may smell it and become curious.
This is an effect which like RandomPages, expose pages which have in effect fallen off the "radar screen" and that are both interesting and currently relevant. As a result those who may not have been aware of the existance or content of the page are found participating as a result. This is particularly true for those who may have discovered this wiki long after the page was first created.
It is a desirable, useful, and GoodThing, when we StirThePot.
Related: http://www.phrases.org.uk/bulletin_board/7/messages/204.html