Possible Duplicate:
Blocking comment spam without using captcha
Most of the time Captcha is either broken by bots or by labor force working as data entry jobs in Asia. And then spam/content bots/scrappers get in.
What are other strong and effective alternatives available?
And I thought about something like on smartphones these days that it ask you to drag to unlock. I think if that can be made in Adobe Flash or maybe using HTML5? .. do you think it will work effectively?
Please note that emphasize is on defeating HUMAN + BOT partnership where human element comes from Asian countries to enter Captcha code or simple answers and then bots come into play.