Yeah, be smart with the tags. This applies to more than just screenshots.
The authors name isn't an appropriate tag, and neither is the title of the work. "The Fantastic Wonder Dirt Hole by the Sea" shouldn't be tagged as "The Fantastic Wonder Dirt Hole by the Sea" because unless its a dirt hole by water none of those things are descriptive of the work. and we just end up with tags like "the, fantastic, wonder, by".
Zactly, the word "the" is an article. It means nothing by itself. It's not an acceptable tag.
The key is to use descriptive words.
Think of it this way. Larry bought a brand new car, a blue BMW coupe with a black interior. We need to describe this car to someone over the phone.
Let's tag Larry's car. "Larry" is not an appropriate tag. It tells us nothing about the car, other than Larry owns it, and who cares about that? "New"? Well, it is new, but once again, it doesn't tell us much about the car. Bad tag. "Brand"? You might stick this in front of new, thinking you'd get "Brand new". Nope, all you get is the utterly meaningless tag of "Brand". "Awesome"? Well, his car might be pretty great, but awesome is a pretty subjective term and once again doesn't actually do much to describe the car. Tagging his car "Awesome" or "Great" might also be kind of a letdown when the person on the phone actually sees the car and maybe it's not something they personally think is so great.
"Blue"? Well, that works, but we have a system that does a good job of sorting subs by colors already, but if it's a superior blue car, okay. Same goes for his black interior.
Here's some good tags for Larry's car: Car. Coupe. BMW, German, Fast, Sporty, Sleek.
I'd agree that 2d doesn't make a lot of sense. To me, 2d makes me think of a simple vector or a doodle/sketch. I don't think anyone searching for 2d would expect that sub, which is the purpose of tags.