22% of Americans have to reply to work e-mails away from work

The off-hours checking of work-related email is not an act generated solely by the volition of the employee.

Some 22% of employed email users say they are expected to read and respond to work-related emails, even when they are not at work.

Blackberry and PDA owners are more than twice as likely to report that their employer expects that they will stay tuned in to email outside of the office.

Fully 48% say they are required to read and respond to email when they are away from work, according to Pew Internet Project.