The rapid growth of mobile technology and its adoption throughout society has arguably been a boon to both employers and employees. When put in capable hands, a smart phone can be an incredible promoter of productivity.

But that doesn’t mean that smart phones are perfect. There’s a reason, after all, that many corporate workers given Blackberries coined the term ‘Crackberry.’

In short, one of the most attractive features of smart phones (24/7 connectivity and communication) is one of its greatest downsides. Information overload is a real threat, and employees are, in many cases, effectively always on the job.

Thanks to legislation signed into law last month, smart phones could now put employers in Brazil in a tough spot. As reported by Mobiledia, the “legislation in Brazil asserts company e-mails to workers equal direct orders from employers [and] labor attorneys say this makes it possible for workers answering e-mails after hours to ask for overtime pay.”

That, obviously, is probably not music to the ears of company executives and human resources departments, and it’s not an issue limited to Brazil. As Mobiledia notes, companies like Deutsche Telekom are trying to cut back on after-hours communication, and some, like Volkswagen, are going so far as to turn off email for employees entirely after the work day is done.

If more companies change their email policies in a similar fashion, it could have profound implications for email marketers. As ExactTarget’s RJ Talyor observes, B2B marketers could see lower engagement for emails sent during non-work hours, while B2C marketers could see lower engagement for emails sent during working hours. For consumers who opt to have a work smart phone and a person smart phone, email marketers could find themselves grappling with a “context” problem.

In the end, to maintain successful campaigns that convert, email marketers may have to get much more sophisticated about segmenting work versus non-work emails, and spend more time evaluating ideal timing for delivery based on this segmentation. In some cases, Taylor suggests, hitting an individual with a message may require a non-email solution.

Savvy email marketers could of course deal with this, and they already look closely at segmentation and timing, but having less flexibility due to employer-imposed restrictions on employee email use would certainly make email marketing more ‘interesting’ for many companies.