Priceline recently announced its acquisition of Kayak, a leading travel search company, which marks its entry into the meta-search space.

FORBES: Breaking Down Priceline's Business And Stock Drivers

However, with the entry of large internet search engines such as Google (which has substantial resources and expertise in developing online commerce and facilitating internet traffic) in the online travel market, the future growth of Kayak and other related companies faces great risks ahead.

FORBES: Kayak Shows Rapid User Growth But Google Remains A Threat

However, with the acquisition of Kayak, it marks its entry in the meta-search space.

FORBES: How Can Kayak's Acquisition Fuel Priceline's Growth?

In the original Kindle, you had a dedicated search button which would bring up a text entry field, then transport you to a page to select how you wanted to search, then to your results.

ENGADGET: Amazon Kindle 2 review

They became portals that used search (and email) as entry points, then beguiled the users who came for those tools into sticking around until they could be monetized adequately.

FORBES: Make CNN The Google Of News: Radical Unsolicited Advice For Jeff Zucker

Students can use it to search for advice, such as the entry requirements for graduate school.

ECONOMIST: Lessons of a virtual timetable

Police have now sealed off all entry and exit points in Multan, and a massive search operation is under way, local media report.

BBC: Asia

In search, Google is now vulnerable because the barriers to entry to its market are low.

ECONOMIST: The internet

The search engine market is a dynamic marketplace with little to no barriers to entry.

FORBES: Move up http://i.forbesimg.com t Move down

All the search engines follow these robot directives, which, while not a perfect security solution, limit the entry points used by the bots and spiders that index the Web.

FORBES: Google Me Not