One problem that I frequently encounter is public officials' use of personal e-mail addresses (such as JohnDoe@Yahoo.com) instead of official e-mail addresses (such as JohnDoe@CityOfVineland.org) for official correspondence. Since e-mails that are send and received by private e-mail servers are not typically retained by government agencies, production of those e-mails in response to future OPRA requests may be difficult if not impossible to fulfill, especially if the officials who sent or received them have since passed away, moved out of town, etc.
In order to identify and correct this problem, I typically submit an OPRA request to an agency for a few random e-mails. For example, I might ask a municipality for "the first six e-mails regarding municipal business that were sent or received by Councilman John Doe after January 10, 2010 at 7 a.m." When I receive the responsive e-mails, I can see if the municipal officials who sent or received them used their personal or official e-mail addresses.
When I find that officials are communicating official business by way of personal e-mail addresses, I send them a letter inviting them to adopt a policy requiring the use of official e-mail addresses. Often I am successful in this effort, as evidenced by my recent correspondence with the Lopatcong Board of Education (Warren County) which is on-line here.
Sometimes, however, my efforts are not successful, as in the case of Haddon Heights Borough (Camden County) where Mayor Scott Alexander, who uses a personal Comcast.net e-mail address, informed me that "as a matter of practice, I do not store sent emails." Even though Mayor Scott's practice most likely violates New Jersey's records retention laws and regulations, there is no straightforward way to have those laws and regulations enforced. My OPRA request to Haddon Heights and the Borough's response is on-line at here.