All of the stories I plan on reccing are older, AU/fusion, and, at most, have spoilers for IM3. So it shouldn't be an issue. :)

But, personally, I try to be very good about spoilers, for all the above reasons. I'm not a spoiler-phobe myself (I'm about four episodes behind on SHIELD, and have vague ideas of what's happening in each) but I do my best to respect others' feelings about it.