Yeahhhhhh this wouldn't turn out too well (and isn't really necessary).
In the end it would either be all troll comments about the person or just people having random conversations on users profiles which wouldn't look good (watching replay comments shows basically what would happen with all of this)
If you want to talk about people you can go in chat or if you want to talk to them directly you can simply PM them but I don't think we need to give people any other chances to create flame topics.