Tripsetc Soon will Join Travel Websites Flash Sales.

Soon it seems nearly every travel site will offer members’ only flash sales for hotels or local deals.

Hours after Priceline revealed it is testing Priceline.com local deals for spas, restaurants and retail offers, two Orbitz Worldwide properties, Orbitz and CheapTickets, disclosed they are launching members’-only flash sales for hotels.

Flash sales are limited-time sales — perhaps a week or a few days — and generally are open only to a site’s “members,” or registered users.

Orbitz says its Inside Steals will offer at least 50% discounts on hotels for global destinations including Hawaii, Las Vegas, New York, Orlando and Cancun.

The sales for registered members will arrive in Tuesday emails and be available on Orbitz.com for a maximum of 72 hours only, Orbitz says. They will be accessible for shorter durations if they sell out.

Sister company CheapTickets, will also offer similar flash sales, although they will be branded Members Only Prices.

No word yet from Orbitz Worldwide on whether it’s eBookers unit will get in on the action, as well.

There is a seeming unending parade of travel sites now getting into flash sales of some stripe. They include Expedia, Travelzoo, Priceline, Jetsetter, Voyage Prive, SniqueAway, Yuupon Off & Away, and now Orbitz and Cheaptickets.

Cynics will ask whether there will be any differentiation at all if major sites are all offering the same trendy new thing?

This issue has been debated over and over, including here in this post about “legacy OTAs.”

Of course, some of these flash sales products are different than others, but the question is still a legitimate one.

At least one travel site, Kayak, went in a different direction.

Kayak, experimented with private sales a year ago, but dropped the idea.

We will implement our own Flash Sales and Members Only Specials on Our Website Soon.