Below is a snapshot of a recent CAPTCHA code that came up.
I'm unsure exactly what the '3' is for, but you get the idea.
This does however highlight the potential of using CAPTCHA codes for advertising or branding. eg. 'TrustRAA' could be one for the South Australian based users (a local advertising strap line for the Royal Automobile Association line of insurance products). Or 'VisitMelbourne' for the international 'visitmelbourne.com' campaign, for example. Or even 'BrinksterFreeHosting', to let people know about Brinkster's free web hosting (with no ads).
Disclaimer: There may need to be other random characters inserted within the CAPTCHA to ensure bots do not guess potential popular phrases (and thus defeat the original purpose of the CAPTCHA code verification).