There's a lot of interesting discussion here - clearly, there's no real agreement on what is appropriate regarding spoilers.
For a variety of reasons, I usually don't purchase/play games until after they've been out for quite some time. By the time I buy, the bugs have been patched, DLCs have dropped, guides and wikis are published, mods are available. I frequently end up getting a package deal that includes all of the DLC at a discount.
When I pop into threads, articles, etc. about games I'm considering, I'm usually looking for information about gameplay and mechanics, difficulty level, who is the MC, what's the world like, that sort of thing. I guess I've been fairly fortunate in that a lot of the material I read through to try to decide whether a game interests me is usually plot spoiler-free - or at least the authors make the effort to mark spoilers so I can avoid them. Even so, I still bump into some unmarked spoilers sometimes, which does put a damper on some of the fun I'd otherwise have with a game.
Basic consideration goes a long way.