pnm wrote:
And the numbers have been pretty stable for a long time,
i.e. about the same number of people join as leave.
I suppose I should promote the site a bit more
I presume some of those are people who just solve a small number of puzzles and then leave, or possibly come back from time to time, but not on a regular basis?
I think most 'hard core' puzzlers are in it for the long haul and don't tend to drop out (Sheldolina being a notable exception to this rule).
Regarding how you might market the website, I'm not really sure how you would do this effectively. I found out about the site by accident due to having discovered Killer Sudoku in a UK newspaper someone had left on a plane from Singapore to London. I'd only ever done regular Sudoku and this struck me as a more interesting variation. I googled Killer Sudoku after I got home and found this website.
I think I only did the Killer Sudokus at first and then noticed the other puzzles and started doing them too. After about a week, I was hooked, but I resisted becoming a subscriber because I felt I was already spending too much time on the site. As I got quicker at solving the problems, the lure of the extra points on offer to subscribers proved too hard to resist and I became a subscriber about 8 months after joining the site.
I don't know how typical my story is, but I imagine it's not totally out of line with how other people got involved.