I have no life.
-They are secluded in their sealed environment.
-They are well know through The Commonwealth, all the way down into D.C., and as far west as The Pitt.
-They seemingly don't care about what goes on outside their walls unless it has to do with tech stolen from them, or tech that "ran away"
-As far as we know they aren't trying to take over any part of the wastes
-They are well known for producing incredibly high tech things
The general lack of other things in The Commonwealth causes others to equate The Institute with The Commonwealth since its the only thing really interesting in the area.
"Looks like Rivet City's latest visitor, a certain Zimmer from the scientifically superior Commonwealth, has finally packed his bags and headed home. Weird thing is, trusted Rivet City resident and head of security Harkness has abandoned his life here in the Capital Wasteland... and gone with him. A case of unrequited middle-aged romance, or some kind of spontaneously beneficial business arrangement? I'd ask the kid from 101, but I hear he's busy oogling some newly obtained piece of shiny Commonwealth technology. Quite a 'coinc-of-a-dink', that..."