I've never really expected anything, not when posting my fics on fandom-specific forums, even less when posting them in generic places where they're more likely to confuse people.

I love to see individual scenes, characters, etc pointed out. Another fun one is questions of any kind. About the plot, or even the intentions behind the writing. I think part of the fun in sharing fanfic is receiving different perspectives on your own creations. This definitely includes critique too. Of course it can be hard to formulate precise and helpful critique but that's often the only critical input a new writer has access to.