I\'m writing what will be an intranet application, and one of its features is roughly analogous to content voting - not unlike what SO, Amazon, and many other sites do.
Well, yes but you need to look at the bigger picture. With a million pieces of CONTENT:
(Size of Content) >> (Size of Votes) : where ">>" means "much greater."
If you have a million pieces of content then that might be a terabyte of data where as the votes are 400MB. Big deal right?
I would also add, if you are worried about scalability, check out this blog:
http://highscalability.com/