I would rather have a tooltip option. It would be neat if a little tooltip would popup with the first paragraph or so of the page you are linking too.defenition of it.
It would add quite a server load though.
It would also massively increase the size of every page in the system, which would cost more in bandwidth and make pages download and render significantly slowly on the users' systems (that's before we factor in the delay for the backend).
It would be a very expensive feature in terms of drawbacks and probably not worth it. Cool, though? Definitely.
HÃnandil