I just received a email about my commitment to the Workplace, explaining the proposal is over halfway there. However, it contains a call to action that's not entirely accurate:
Committing is the only way to get access to the private beta, and every committer moves the proposal one step closer to launching. Hurry! Once the private beta begins, new sign-ups will be closed until the site goes public.
Committing isn't the only way to get access to the private beta: people in the private beta can invite people once it starts (which also means sign-ups aren't closed before the site goes public).