On the homepage of a site (movies.stackexchange.com for example) the Top Questions defaults to Active.
- Active is anything that has been Asked, Answered, Commented, or Modified recently.
- Hot are questions with the most views, answers, and votes within the last few days.
To me, as a user, I would have more interest in the Hot tab rather than the Active tab because the Hot tab is what everyone else is looking at. Should the home page really default to Active? IMHO I don't think so.