Dr Paul Voninski, of the State University of New York at Oswego, said the amount of information, whether photographs, blogs or tweets, people uploaded online raised the question of whether a "digital will" was necessary.
"When things are put on the internet they stay on the internet and the question is ... what is going to happen to it when we die?" he asked the audience.
This problem could be seen with the meteoric rise of Facebook, for example, which now had at least 800 million users.
Dr Voninski said by extrapolation this meant more than 15,000 Facebook users died every day, which was creating a huge problem of "ghost users who appear to be alive but are not".
There were also privacy issues over who should be able to access what you put online when you died and whether people would, for instance, want their families to see "everything" they put on the web, he said.
Dr Voninski also explored the growing sector of software applications or "apps" associated with death.
One app called "Death Switch" enabled users to automatically have information such as passwords emailed to designated people when they died.
It could also be tailored to send out everything from "unspeakable secrets" to "last words in an argument".
Another app called "EnemyGraph" automatically sent messages to your enemies when you died, which could include people you knew personally or public figures.
At the moment the most popular recipient for these death messages was Canadian singer Justin Bieber.
Dr Voninski's talk came on the final day of the "Death Down Under" conference, during which about 60 people, including academics, nurses, doctors and funeral directors spoke about death, dying and bereavement.
