Thanks, kscalef, that's really useful feedback. I had heard similar things about TCL but from people already predisposed against perl and other "messier" languages. Also I agree ACS seems very complete. Interesting you stopped using ACS -- why was that?

I guess when I say "extend," that's a little vague. Let's say I want to start a community-driven site devoted to, using a common example, beer. In addition to articles and Q&As and comments and reviews and all the usual ACS content, I also want the database to hold information on the beers themselves, including brewery and type (porter, stout, ale, lager) and so forth. Then one could query beers on all sorts of different criteria, from location to type to the date it was first brewed.

I know how to do this in Perl using various modules, and I know the SQL that would be required for the DB stuff. I guess what I worry about is integrating such new "object" types with all the other services ACS provides, ranging from full text search to the comments and reviews.

Another example would be customizing the full text search results to sort by date, or to screen for certain terms ("home brew" automatically puts the home brewing howto and forum first, for example). I could do this in a snap with Plucene but ACS -- not sure how easy it'll be.

Anyway, thanks. At some point I guess I'll have to try this thing if I decide to stray a bit off the Perl path. It just seems like a very mature platform even though it's not Perl and Not Invented Here ;->