They finally gone

They have gone for two days and I scarcely remember of them. All of them are happy to leave I think, they didn't leave me any words, they said, "You can contact me with MSN Messenger...".
But I don't use MSN, and none of them had learned to use it either.
Now I am concentrating on writing a boring thesis about Japanese economy and I don't think of them. What is Lost 10 Years in Japan?
Where have all the flowers gone?