I think you're comparing apples with oranges. You're referring to filesystem de-duplication I presume which is a something of a different application albeit the technology is similar-ish in concept. Not played with 2008 particularly so couldn't really comment. I don't spend a lot of time tooling around with servers any more, and if I do it's usually something a little more heavy-duty than Windows.
Oh lah-de-dah wouldn't be caught with a Windows OS...
I was talking about BranchCache:
Windows Server 2008 R2: Branch Cache
and was wondering, since you had obviously done some research on the viability of the Riverbed product, whether built-in 'freebie' tools like this negated a certain percentage of the Riverbed USP given it's noted expense.
(and I too don't see why we need to pander to the lowest common denominator in IT terms for 100% of the threads, and would be up for some BGP troubleshooting if necessary - it's not as if we're drowning in semi-advanced IT, is it?).