"There's this..." vs. "There's a..."

Hi everyone! I am new to this forum and am so glad to have found it.
Anyway, I have a question that I've been scratching my head over. You see, I have this tendency to start my sentences a certain way whenever I talk about a certain subject. If I'm going to be talking about a male friend of mine, I will say, "There's this guy I know..." or if I'm talking about an article, it'll be "There's this article that I read..."
I was corrected and told that saying "there's this..." is actually improper English, as that indicates that the subject is actually right near you. Since I'm usually just talking about a subject that's not physically near me at the moment, I should say, "There's a boy that I know..." etc.
I know that the logic behind choosing "there's a" over "there's this..." is pretty self-explanatory and clear, but I'm wondering if "there's this..." is actually improper English. I hear it so often (and actually see it in articles), that I never really gave a second thought to it. Is "there's this..." actually improper, but due to overusage, it's become accepted?
Any insights/comments would be much appreciated!
I have so much to learn 🙂 Thank you!:smile:

I believe “this†is a definite article like “theâ€
where this refers to a specific object among objects like it.
I saw a man, not just any man but this man.
A read an article, not just any article but this article.
I think you provide more information when using this suggest you know the subject directly.

But does "this" have to refer to something that is physically near you? As in you point at someone/something and say "'this' boy..?"

does “this†have to refer to something that is physically near you?
I don't think so
http://www.brainyquote.com/words/th/this229890.html
I suppose one could use "that" for more distant objects.
I was corrected and told that saying “there's this…†is actually improper English, as that indicates that the subject is actually right near you.
That's ridiculous! The correction of your speech was unwarranted. Saying “there's this boy I know†is akin to saying “there exists a boy whom I know.†As the Collins dictionaries put it, “there†can be “used as a grammatical subject with some verbs, especially be, when the true subject is an indefinite or mass noun phrase following the verb as complement.†In this case, “a boy that I know" is the indefinite noun phrase. Collins gives as an example “there is a girl in that office,†which is remarkably similar to the phrase you're asking about.