You're welcome to everyone. Twitter serves us again.
As mentioned by The Sims Community, it's like they're giving us Ambitions and Open for Business all rolled into one which is awesome!
I would imagine, though, that trying to do two or more active careers at the same time might be a bit much. It will depend on the interactions available to the off site sim (like if you're with one active career sim and the other sim in the household is also in an active career but grayed out - maybe they'll have appropriate interations available on the off site sim).
I've VERY excited for this expansion though. Looking forward to more official information.
Addition: I'm also laying money on either a whole new town or new neighbourhoods for the existing two towns to handle the new buildings. This is when the Sims 4 system will shine. Add new venues? No problem, it's a new neighbourhood so no lagville like Sims 3.