Only a matter of time before all the OTA's get into the travel flash sale game. They have emails of millions of customers, why not put them to use?

Insider Steals from Orbitz is the latest in travel sales, you need to register your email address in a normal Orbitz account to sign up. Exclusive? No. Good deals? Probably. Leading the market? Not at all.

I think the Expedia / Groupon combo Groupon Getaways has more potential for success.

CheapTickets.com has also launched weekly (not daily) members-only flash sales called very creatively: “Members Only Prices.” So original.

Who's next?

Travelocity? Hotels.com? Lastminute.com? My money's on Travelocity.

Keeping score? Here's a complete list of Travel Flash Sale Sites.