Weird Googlebot behavior

[jimpoo]

I'm seeing Googlebot append a strange string "

!b_id=17

" to the end of some of my website's urls.

Take a look at this log:
---------------------------------------
66.249.71.39 - - [21/Jan/2005:23:33:30 -0500] "GET /blue_widget.html!b_id=17 HTTP/1.0" 200 23285 "-" "Googlebot/2.1 (+http://www.google.com/bot.html)"
---------------------------------------

It looks like Googlebot append the sting to some urls randomly, not all urls.

Anybody saw this?
And what is its purpose?

[Brett_Tabke]

What happens when those urls are requested?

[Critter]

You have to remember that Googlebot tries to get pages that have been linked to elsewhere, elsewhere including other pages on your site.

If the links from "elsewhere" are improperly formed you'll see Googlebot trying to retrieve them anyway. I get a lot of requests for pages with querystrings appended to them; querystrings that aren't from my site.