Honestly, I never understood why authors put chat rooms in their story. I don't mean when the characters are talking over KKT, because that is sometimes acceptable. I mean when they finish a chapter or story, they put something like this:

So this is a little bit conversation between me, Lu Han, Sehun and Jessica. haha~ I’m too bored. just read.

Lu Han: I said, I’m going to kick you right?

Me: Aniya!!! I’ just defending Sehun in this story only!

Sehun: What??

Me: he said you are in this story. In front Jessica.

Lu Han: Its true! You are interrupting my Jessica.

Sehun : Heh! In this story only. SicaKris!

Me : Yes, sir Sehun??

Sehun: I want you to write another story about HunSica after this.

Me: Erm…

Lu Han: Pabo. She ship Kris with Jessica. not us.

Me: Hey you two! Don’t judge my username. I wrote a lot of HunSica and Lu Sica you know.

Sehun: Give us a few tittles.

Jessica: ert Author; LuSica, Comeback Hot Summer HunSica.. but I think you had a lot of LuSica.

Lu Han: *smirk* what? you don’t like it. this kid love to use us as her character.

Jessica: I prefer more KrisSica. I don’t want Kris be my brother again! He’s too damn handsome.

Sehun: I want to kill hyung now.

Me: why I feel ignored?

*tadaaaaaaXD its finished. Haha~ forgive me. I’m bit crazy since day.

It's useless to put at the end of a story. If you want to advertise your other stories, just put an author's note at the bottom saying something like "If you liked this, check out some of my other [insert pairing here] stories!" or something like that.

Honestly, my summary of this chapter is treat fanfics as if they are real stories. Would a real author put author's notes randomly in the middle of their story? No. Would a real author put a chat box with him and the characters advertising his other stories at the end of their story? No. There would normally just be a page in the back of the book listing their other works with a brief summary. Do that instead.