usernames as keys
Forgive me if this is answered in the book (my copy hasn't arrived yet, but I've been pouring over the source code). It seems to me that storing usernames as the keys to user records (as opposed to say an int) is highly inefficient. Sure, in ASP.NET membership, the username is fixed, but doesn't this add a lot of unnecessary data to every single forum post? For a highly active forum (say 50,000 posts), you'd be storing nearly 10MB of username data alone in the database.
I'm curious what tradeoffs went into making this decision.
Love the site and what I've seen so far of the book online, by the way. I can't wait until my copy arrives!