I am currently working on a long driving animation which I would hate to hit an unknown limit after spending the time to set it up.
The practical limits are that you can only have a maxiumum of 1000 ticks on the timeline.
That doesn't restrict the number of frames that you can render or the length of the animation in time, but it does restrict the number of keyframes you can actually place.
You can make animations any length you like with Bongo, although it isn't really designed for long complex scenes…
Bongo 2.0 should fix that when it's released.
Getting it to play on a website directly is just a case of saving as MPEG.
Andy le Bihan