Private sites are always subject to arbitrary censorship, and the increasing fragmentation into disparate forums and bulletin boards makes it hard for any one person to keep up with what is being said. By all means archive your more substantive comments here and/or realclimate.org, but IMO debate belongs in the public domain.
Usenet may be awful, but it is still probably better than the alternatives...
As it happens, I've been thinking about this myself recently, prompted by the number of venues I've been reading and the difficulty of keeping up with them all. The other irritation is that even if you read them, posting replies is tedious, with the variety of identifications in use.
So... in chronological order of me... I've participated in:
The newsgroup sci.environment. Advantages (as JA implicitly says) is that its a primary forum available to all (via groups.google.com if nowhere else) and that everyone is equal. Disadvantage is the high noise level. The latter isn't as bad as you might think. Its probably a problem for newcomers, but once you've been around a bit and know who's who, you can blip though the junk pretty quickly. At least you can using tin; it may be harder via a browser. Though as I write this the current top post is an example of the kind of offensive trash that is unavoidable on an unmoderated group.
Wikipedia, in particular the pages related to climate change. Advantages: as above, anyone is equal. Being newer, its a bit less primary than sci.env. I like it because its constructive and complements sci.env. Sci.env suffers in that good material just disappears into the archives; with wiki you can build up decent pages, but there are talk pages for discussion too. The disadvantage is that any old bozo has the same editing rights as me; and when we disagree and reason fails there is little alternative but an edit war. A few other sci.env folk have contributed there too. One could argue that discussion on wiki is fragmented amongst the various pages, whereas in sci.env its all in one list, so you see it all. Still, maybe it helps to concentrate on one topic at a time.
Blogs. Advantages: you get one persons POV, and responses if you choose to read them, which makes for clearer discussion. Also, you get to read a fairly intelligent and coherent posting, assuming you haven't chosen some wacko's blog of course. Disadvantages: very asymmetrical relationship (the ones I read don't abuse their position by censoring stuff they don't like (within bounds) but still there is the feeling-before-posting that you may be wasting your effort because someone might just cut your comment). Also, there are so *many* of them! In order of me reading them, first was Quark Soup, which I first started reading in Nov 2003 after reading a post about it on sci.env. That was about the MBH/M&M controversy and QS had the breaking news. Sadly QS suffered a data-loss of its archives so I don't think you can read those old posts now... ohhhh, I've jsut checked, you can get them via The Wayback machine. Splendid. Anyway, where was I? Oh yes... so, tracking QS, and the comments on it, was not too much of a task. And it was interesting that the community of people there (and blogs do seems to attract communities, for better or for worse) was different to sci.env. But then (via QS I think) I found...
(Aside: I've made a point at attempting cross-fertilisation, by mentioning wiki on sci.env for example. But its slow.)
Deltoid, Tim Lamberts blog. Its mostly about the evils of John Lott etc, but he found time to take apart some of McKitricks errors (you want to see an alternative side? Try McIntryres site, though with caution). So now browsing Deltoid went on my list. "Fortunately" both QS and D don't post climate stuff too often.
Then along came RealClimate to which I contribute, and the workload went up rather more.
Then there are other blogs that I found incidentally and occaisionally visit, with the somewhat guilty feeling that I ought to take the time to read them more, but I don't have the time, so I have the guilt. But only mildy. Examples: John Fleck and Prometheus/James Pielke.
So... were does that all end up? Sci.env and wiki stand up by themselves, so there is no need to worry about them. But the blogs are badly in need of some method of at least integrating their output. Perhaps a newsgroup sci.env.blogs, to which posts like this, and QS, and Prometheus, and so on, are automatically posted as they are put on the blogs. That *would* be a good idea I think. I wonder if its possible? I get an email from me whenever I post stuff here; in theory I could either procmail that off somewhere, or maybe blogger could redirect it for me, and surely there are mail-to-newsgroup gateways? Gmane for example. If anyone thinks this is worth trying, do let me know.