Mittwald CM Service uploaded their latest version of the webforum extension mm_forum to TER. Eight weeks after the first alpha release, the extension now entered a beta state, but is actually called "almost stable" by the developers themselves.
The extension in particular drives the popular german TYPO3 forum at www.typo3.net
and thus seems to be fit for higher load environments. Unfortunately, I don't have any statistics (like traffic
peaks) so this assumption is pure theory. According to Mittwald, 19.000 users have registered at typo3.net and
230.000 postings have been written yet. But without any knowledge about the data distribution, this is just a bunch
of numbers (probably growing since 2001).
The forum is shipped with a build-in crawler and search engine, optimized for searching forum postings - a wise decision, since indexed_search is almost infamous for causing heavy load and timeouts in large scale environments.
A first look at the database tables reveals the use of indexes for some columns/tables. Indexes can speed up SELECT statements but are yet rarely implemented in any extension. Anyway, thanks to the efforts of core-dev Dmitry Dulepov, they are meanwhile common in core and sysext tables.
The extension is available via extension repository or directly via typo3.org.