Gadget, I know it was always possible to look at unconnected trees, but sometimes taking just a quick look at new matches page showed no tree - on more distant matches I couldn't always be bothered to click to see if they had an unconnected tree or not, just skimmed them by (fault mine, I fully accept, but when you have several thousand matches, you have to use your time wisely!).
As for ancestry not providing surnames from these unconnected trees - they cannot find ancestral surnames in common unless the match attached themselves to a tree. This can be either public or private tree, surnames and places theoretically show up in both, though it is 'flaky' to say the least.
EOL I think is meant to be End of Line.
Your best bet, if you want to follow it through, may be to ask your match if they will connect the tree to themselves or identify to you where they are in the tree, if they are not the home person.
Regards Margaret