Everyone wants their site to be found by google, right? Who wouldn’t want more free traffic delivered to their site? The goal of getting onto page 1 of the SERPs (search engine result pages) is such a holy grail, that a whole service industry called search engine optimization has come into it’s own.

But traffic doesn’t always come from the search engines. And some online businesses are not at all interested in marketing to just anyone, but rather just to a targeted clientele that comes to them virally rather via search.

Meet invitation only sites such as Rue La La a luxury e-tailer that seeks to promote an air of exclusivity. To become a member, you have to be invited, and only then can you have access to its discounted designer goods.

Putting your site behind an authentication prompt, which Rue La La has done, is one way to hide your pages from the search engines. Another is through directives in a file, robots.txt, you place on your site. Sites such as Gilt Groupe, another invite only site have excluded many of their site’s directories from the spiders.

So if you are searching for a killer deal on that Gucci bag online, be aware there are certain sites that are completely hidden from you unless you are “in the know”.