I was wondering if both meant the same thing, and if there's any difference between the two, what they were, because as I see it, it's pretty much the same thing. Saying "post under my real name" should mean the same thing as "post with my real name". Am I wrong?
For example:
I am posting under my real name on the English Language Learners stackexchange.
They do mean the same thing. I think under is more commonly used in this context. You could also substitute the word using and that would be fine as well.
I think that the history of usage may be that to "post under" comes from the term to "write under" a name - because the author's name would be on the cover, and their writing on the pages underneath the cover - it is a visualisation of posting content physically/spatially under the author's name.
"Post with" is more abstract - indicating an association of the name with the content being posted - though one could interpret "post with X" to mean that it was a collaboration with X, or that X did the mechanics/delivery of the posting and someone else was the author/creator, arguably you could inject alternate meanings that are not incorrect.
