Having issues with Twitter on your BlackBerry Z10? Just seeing that 'spinny' thing? The CrackBerry Forums have several threads on the matter already. The good news is that BlackBerry is already aware of the issue and working to get things back to working order as soon as possible.
At this point, there isn't an ETA for a resolution but at least you can take solace in knowing you're not alone. In the meantime, other apps are working so now might be a good time to head on into BlackBerry World and give a different Twitter app a go. We'll keep monitoring the situation and update when necessary.