@sindum that said, after thinking a bit more, I realy think I would like the three boxes (could be a dropdown that activate or deactivate a category as well, but tha may be bad UI) and be able to choose what I am in the mood for today. Sometimes I just want to know what is going on with my friends, and not necessarily have it all cluttered up by a crapload of posts from the groups I participate in, and on those days I most definitely don't want the world to interfere as well. If three checkboxes are impractical, three tabs - then I can at least switch between the ones I am in the mood for today.
