A survey on passwords was carried out for the Infosecurity Europe trade show. The survey data was gathered by questioning commuters passing through Liverpool Street station in London and found that many were happy to share login and password information with those carrying out the research.   

Passwords - 70% would disclose this for a bar of chocolate

http://news.bbc.co.uk/2/hi/technology/3639679.stm

More than 70% of people would reveal their computer password in exchange for a bar of chocolate, a survey has found.   It also showed that 34% of respondents volunteered their password when asked without even needing to be bribed.  A second survey found that 79% of people unwittingly gave away information that could be used to steal their identity when questioned.

Family names, pets and football teams were all used by those questioned to provide inspiration for a password.  The survey found that, on average, people have to remember four passwords, though one unlucky respondent had to remember 40.  Many adopt very unsafe tactics to remember these login names. Some of those questioned simply use the same password for every system they must log on to.