Why this happens on my profile everytime i click it?

[CuriousAsker95]

The URL is my profile's(i don't tell it for obvious reasons)but there is an '?ref=tn_tnmn' (without the ' )right next to my profile ID.i delete that and i press Enter and here we go,this is my profile!If i delete one letter beyond that ?ref=tn_tnmn (for example my last profile's ID letter is "e" if i delete that says "the page you're looking for isn't available"but if i don't do anything just reloads my profile.so wtf is that ?ref=tn_tnmn meaning??)so i notice that this happens ONLY when i click it from the main facebook page(http://www.facebook.com)f.e i'm on the main page and i'm looking the feeds and the pages..i click my profile and the URL is my profile's ID but also this ?ref=tn_tnmn so i delete the ?ref=tn_tnmn and i press enter,that's my profile again.What's the point in all this? i notice that the last 2 days..it's kinda annoying because when all the URL load (my profile's ID plus the ?ref=tn_tnmn)it kinda lags but when i delete the ?ref=tn_tnmn and i press enter it starts almost immediately..any reasons why that happens?