[timskii]

To clarify my optimization comment slightly:

It may be optimized for memcached, since all those individual pieces of user information rarely change, so all those queries will fall straight to the memory, which becomes ruthlessly efficient. If all the information used on each page is queried together, memcached would fill up with page-specific results, rather than user-specific results: So many individual queries is logically more efficient if you are caching the results of those queries.

There is some logic in this: The structure still works reasonably well on smaller (often shared) setups, where caching can be technically difficult to implement. However BBPress is aiming to support large scale deployment, which is almost inevitably going to mean the use of caching. If you can only write the code optimally for one of those users, optimizing it for someone that can save whole machines in the process, is sensible.