You have heard that phrase as it describes an overheated IPO market.
I have heard it as I meet founders of some start-ups that believe they are close to an IPO, even though they have little to no revenues. See this Wikipedia entry.
Tulipmania is and was real.
Here is a fantastic documentary film that deals with the actual phenomenon of Tulipmania, in an age when tulip future contracts were becoming a part of a trading currency. The market expanded and died - in short order.
This is a very instructive film for us all to see, on SnagFilms.com. Watch this weekend; be careful where you invest your money.