So I really do crave comments and wish there were more of them -- in fact, let's break that sentence there.
It's basically impossible to read this blog without knowing that I have money troubles and could really use donations. My boring asking for donations post was a mere nine days ago and a few people were able to step up and donate and of the three looming not-good things on the near horizon one is effectively dealt with so "Yay!" (And thanks.) But for everyone who couldn't/can't donate, which I totally get (I intimately understand having no money to spare), if you're wishing for a way you could help: comment.
Seriously. I crave feedback. Without it there's just a void. It's like no one read the thing or no one cared. It's complete emptiness. Comment on new things, comment on old things. Say, "I liked this part," or, "I didn't like that part," or, "This turn of phrase was neat," or, "This feels like it was influenced by [X]," or, "Was that a [Y] reference?" or, "I think [this] should happen next," or, "I don't understand [Z]," or, "I don't know why this makes me think this but: Lobster," or whatever the hell comes into your mind.
I will appreciate it.
That being said, let me return to the first sentence and actually finish it this time:
So I really do crave comments and wish there were more of them, which makes me wary of saying anything that might discourage them. However, if you're saying something that is contingent on certain details that you don't know I'd appreciate if you didn't just pull random assumptions of of your ass. Yes, I'm talking about the Avengers plot hole thread, yes it is entirely possible that this entire post has only one person to whom it applies and that person will not read it anyway.
But for general consumption, there are things you can do when you don't have all the details. It is a mistake to think that you need to have all the details to respond, you can totally respond it just needs some precautions.
Consider all of the people who have never read Left Behind but follow and comment on Fred Clark's deconstruction of it over on Slacktivist. They bring valuable insights and have created a vibrant community, this in spite of the fact that most of them have no idea what's said in the sections Fred doesn't excerpt and could thus be missing critical details.
Just because you don't know doesn't mean you shouldn't comment. What it does mean is that if what you're saying depends on something you don't know you should take that into account in your comment. Absolute simplest way, which requires almost no effort: "If [thing I don't know] then [comment]."
You've made your comment and contributed to the conversation without asserting that a potentially false thing is true. If the thing is true, then we can move on from there, if the thing is false perhaps it will start a brilliant tangent about an alternate universe in which it is true, if it's unclear then you've provided your opinion on one of the possible cases.
Very, very easy. Of course it also means that you might make a comment that adds little.
For example, using the above the comment that got me to write would have started, "If Jane Foster's usefulness is dependent upon direct access to the tesseract..." and since Foster's usefulness is not dependent on access to the tesseract (direct or indirect) it would still be the case that nothing in the post applied to the movie as it exists in real life.
Of course, maybe phrasing it that way would kickstart a discussion on the difference between characters that are useful in themselves and characters that are useful only in relation to a certain thing and who knows where things might go from there.
But the point is, maybe you don't want to go the, "If ... then ... " route but you still have a comment or argument whose truth value is dependent upon information you don't have. In that case one thing you can do is to look it up.
This is not always as easy or as reliable as it may seem. I remember at one point I had to look at every reference to the word "hair" in Twilight (using searchable version of the book online, cross referenced with a physical copy of the book where I could actually READ ALL THE WORDS for context, which had inexplicably mashed the text with that of a completely different novel) just to see if my comment would apply. I definitely should have just If-Thened there. Way too much work for the pay off.
On the topic of reliability, recently --this month I think-- Ana Mardoll pointed to a Wikipedia description of an event in The Voyage of the Dawn Treader that was wrong in every important respect. Someone using Wikipedia to look that up would thus be led astray.
But, in general, looking up details you're not sure on is either pretty fast and not that unreliable (any even marginally accurate description of the movie Thor would have revealed that Jane Foster's usefulness was not dependent on access to the tesseract, for example), or quick to let you know that the information you want isn't easy to get to. So it's a relatively safe route. Safer still if you point out, "Wikipedia tells me [X] so [comment]."
The point here is that not having all the details of the source material is not a barrier to commenting on something here, but if you don't know please don't pretend you do know. Comment, but either If-Then your comment, or try to look it up, or do something else so that you're not asserting as facts things which may or may not be true.
Also, it's perfectly valid to disagree with me, but if you disagree with me by basing your argument on things that are not actually true I'm going to have a hard time taking you seriously.