The single player local world list already includes the seed of each world, while the server list does not.
I think an easy way to retrieve the seed of the world of a server might be useful. Sure, the server owner may find it in the server log and in the DB, but not any server owner is an IT professional (legitimately), and some might have no idea where to look and how.
Reasons for this can be:
1) The seed characterises the world and, even if not everybody is interested in it, it is a relevant datum about the world itself.
2) It happened to me that I would have liked to reproduce locally the specific terrain of a server, but I could not obtain the seed from the owner without bothering him too much.
Having this datum readily available would not raise any security or privacy issue, I assume.
