For a similar project (http://mailarchive.activestate.com) we too use a MSSQL back end, for various reasons similar to Chris. I'm not worried about it, once upon a time I tried to stick everying in the ZODB. To me one of Zope's great strengths is it's portability and connectivity to other databases and storage systems.
That's very true :-) ...however, ODB's seem good for tree-like data, probably better than RDB's, which are better suited to tables. While the mail messages themselves are tabular, the threading, which for me is _the_ most important part, is very tree-like and so, again for me, would sit much more nicely in an ODB. Now, the Catalog, as well as providing a very easy to use interface, is great for indexing tree-like data, but sadly its performance ain't that great for big numbers and/or complex searches right now. If it was lightning fast, better documented and had much more powerful searching capabilities, it would be Zope's absolute killer feature. Well, I can keep dreaming, I suppose :-) Anyway, all Chris P's work is bringing that closer, so thanks for the changes so far, I'm waiting with baited breath for those to come ;-) cheers, Chris