Rotation as a vector
It's an oldie, but goodie...
To summarize the precisely worded ozogg:
1. Linear and angular positions are vector quantities.
2. Linear and angular distances are scalar.
3. Linear and angular velocities are vector quantities.
4. Linear and angular accelerations are vector quantities.
When we talk about rotation, the question, as ozogg asks, is what type of rotation are you talking about? An angle? A velocity? When you define that, you pick from the list above - an angle is scalar, a rotational velocity is a vector.