Watch what you write - those e-mails and instant messages may come back to haunt you. In a recent trial in Federal District Court in Florida, an instant message between two parties to a business contract were found to have made a major modification to their contract. A more complete report can be found here. One party to the exchange didn't like the court adopting what it deemed to be a modification of a prior written agreement - where a contract required any modification to be in writing, the court found that the IM exchanges satisfied that requirement even though they were very cryptic.
It is amazing how quickly people dash off messages, forgetting they may be read much later - the electronic form allows speed without much consideration. Or they make an agreement, but later forget they have done so. And once the message is turned into electrons, it can last forever with endless copies being made and transmitted.
In Family Law, we see people post things on their Facebook pages or send what they believe to be a witty remark - usually we see them for the first time when someone attempts to produce them at a hearing. They can sure be embarrassing.