Hi

I want to know what is the use of Google API key , presently I am working on my website SEO, is it useful API key?

They're used for Google Rankings - but unless you already have one, you're out of luck because Google isn't giving them out anymore.

Vasily

:) :) I se this a lot, what does it mean?

You can read more about the Google SOAP API key here. You can check a web page's Google ranking without a SOAP API key at this new Google page rank page.

If you're so inclined, you can read about APIs on this Wikipedia page, and about SOAP on this page.

EDIT: I highly recommend if you want to track your web site's stats getting a Google account and signing up for Google Analytics. They'll give you code to insert into the pages you want to track. Probably the best stats package out there, particularly if you're using adwords.

Vasily