The normal way that a blog works is that the blog owner starts each new thread with an initial post, and the general public can then comment on it. I proposed initially that anyone who wanted a new thread on a particular subject could put a comment about it in the new thread suggestions thread, but few people have taken me up on that.
I've now noticed, rather belatedly, that I can invite particular people to become Contributors to the blog, in which case they can start their own threads. If you're interested in doing so, let me know, preferably by e-mail, because I'll need your e-mail address in order to issue the formal invitation. My address is here.
In order to be a Contributor, you need to register as a Blogger user, which is quick, easy, and free. You may also need to learn a little about how Blogger works; I haven't found it difficult myself.
As an alternative, you are of course free to start your own blogs. As this is my blog, I retain a certain amount of editorial control over it (I can delete stuff, etc.).
I've already added Alan Davis as a Contributor, because he's in charge of the Reunion and will probably have things to say about it.
I thought of setting a Fiendishly Difficult Exam for prospective Contributors, but gave up the idea on realizing that I'd probably fail it myself. I have fond memories, though, of the Assassins' School final exam as described in Terry Pratchett's Pyramids.