When they first did the linking option, I panicked along with everyone else, since they had left open the option to share comments on FB on friends locked and private LJ entries.
That was not cool.
However, I have realized that now you cannot FB link comments to LJ private and friends locked entries. That is very cool. They must have received plenty of complaints, and they fixed it.
The point is, I have now been playing with the option of sharing on FB the LJ public entries via the little box at the bottom of the LJ posting box. I could have it set up for automatic, like WordPress does, but I prefer to have it optional. That way, if I have something in LJ that I don't particularly want to cross-post, even if it is a public entry, I can do it. And if I want to share, I can just click away.
Yup, I am liking it.