used for lack of a better word in a conversation. can express 1)indifference, 2)actual interest, or 3)kill time before having to actually respond with a complete sentence (each indicated by the user's tone and manner); excellent word choice option when you do not want the person you are talking to to be able to say something else.
1)"I like to study." - "Interesting..."
2)"I got 10 kinds of nasty at the party last night!" - "Interesting...were there a lot of hot guys there?"
3)"I have 3 cars, 2 bikes, and I am a personal trainer." - "Interesting (check out person)...so what was your name again?"