(Whoohoo, my first post in the The Jungle!)

I have a question: I receive the occasional PM and email with questions and requests, which in itself I have absolutely no problem with (quite on the contrary, it can often be inspirational or help discover bugs). However, a surprising number of these messages are what I perceive to be lacking in etiquette. I've learned that a letter, even an informal one, requires an opening, the main text, ending, and signature. And I'm not overly picky I reckon, something like "Hey, [text], cheers, [name]" already makes me happy. But when I receive messages that consist only of the text (one-liners like "How can I install x/y/z?") then this sounds rude to me and I tend to not even bother to reply.
Now to get to my actual question: Am I on the wrong track here? Have times moved on and this truncated style of communication has become acceptable when contacting strangers? I'm not a native speaker of English and only very rarely use "social media" so I'm hoping somebody here will share their opinions.
Cheers!
Michael