[tlug] CAPTCHA on keitai

[Dave M G <dave@example.com>]

TLUG,

Just wondering if anyone knows if there is any common way of handling 
CAPTCHAs on mobile phones, or if it's any different than on desktop 
computers.

I ask because a lot of CAPTCHAs I've seen are seemingly a little too 
large for a lot of keitai screens, and the ones that do fit are 
potentially to easy to crack.

So if one has a site accessible by both mobile and desktop, what does 
one do to ensure people who register are people?

Thanks for any advice.