At the same time, we likely want to avoid the MySpace "Top 8" drama. But just like any currency, if there is some limit, it has value. It has an additional value of making it more difficult for bad actors. Of course, there is no thing stopping a bad server from compromising these rules but
a) They'd have to be very careful about timestamps which could be verified (not impossible but again, harder)
b) They would likely all be to people you don't know so have very little value.
The reason I like Ben's Endorsement proposal is that it's much like "rel=me" links. a simple bidirectional construct that is hard to spoof.