googlebot gets the ability to submit forms on some sites.

Crawling through HTML forms

Specifically, when we encounter a <FORM> element on a high-quality site, we might choose to do a small number of queries using the form. For text boxes, our computers automatically choose words from the site that has the form; for select menus, check boxes, and radio buttons on the form, we choose from among the values of the HTML.

bolding is mine

Just had read about that topic in Matt cutts blog. The next target of good indexing is drop down tables. Matt explained about that thing very well in that post.

Yes, Thanks

thanks for the info! google always surprise us!