Google Search Engine to protect automated request - but why me?

Today i was searching on "mysql data generator" tools using Google search. Suddenly after 1st or 2nd search result page i took more then 20min to click on 3rd page request by clicking the NEXT button in Google Search result page. And here i faced this screen for the 1st time - a page of 403 Forbidden message of Google - We're Sorry! . Even after entering the 1st CAPTCHA value it asked 2nd time to enter the CAPTCHA.



Did you faced this ever doing any Google search before? I need to reproduce this step manually. Not sure why my usual Google search appeared to be like an Automated Request as like as a Computer Virus or a Spyware Application or whatever it claimed? :) Really interesting!

And is it really the way Google gonna verify each and every search click using a CAPTCHA? :) I really love to search anything comes into my mind to search in Google rather using Live Search, Yahoo search or any other search engine. But is Google out of their Search Engine bandwidth? :)

May be i am missing any other important point here. Want to know - Why this verification is really important to Google? :) And what really made Google to identify me in this way? :)