I have decided to follow the excellent example of Terence Tao and start up a blog. For the moment I am too busy to do this properly, because, with the help of June Barrow-Green and Imre Leader, I am editing a book called The Princeton Companion to Mathematics. However, it is partly for that very reason that I want to set up the blog. It is somewhat hard to explain what the book is, but if you want to get quite a good idea, there is a substantial (though out of date) description of it, with several sample articles available here. You can get into this site with userid Guest and password PCM. Comments welcome. A sufficiently sensible comment could even influence what goes into the book, but I should warn that, because we are at a rather late stage of the editing process, I no longer have much room for manoeuvre. So I may end up having to say, “Yes, great point, but unfortunately it’s too late to do anything about it.”
Actually, I hope that the PCM blog will really come into its own after the book comes out. In particular, if you feel that there are unfortunate gaps (as there undoubtedly will be) then maybe it will be possible to do something about it online — I might even start up a wiki consisting of PCM supplements. (The distinction between that and the regular mathematics articles in Wikipedia would be some kind of certification that an article had reached PCM levels of comprehensibility. I’d probably be unwilling to put in the sort of editorial efforts I’ve been putting in over the last few years, but would try to distribute that task by using the blog medium. If you are reading this, maybe you will have a suggestion about how to go about it — in particular, I don’t yet know anything about the technicalities of this kind of thing.)