TCL, I don't know what the 'correct' number is. As I've already suggested, I think some of the new ones are unnecessary. But I guess the optimum number would be where everyone could see at once where to post their questions, and where any would-be responders would go to exercise their expertise. That seems to be the direction we're heading. I never went to most of the old Topics, on account of knowing little about Motoring and less about Adverts. Now, there are even more I don't visit. But this is no loss to anyone, least of all myself. Dot can answer genealogy questions, Quizmonster can explain word origins, and Octavius can elucidate the finer points of Spartan warfare, all without wasting their time ploughing past individual questions, in broader Topics, that don't concern them. I think it's swings and roundabouts; and I don't think any individual Topic or Subtopic is a waste of space just because not a lot of people go there - the point is that the few who do go there should know their stuff.