Nour has been writing spirited dispatches from his jail cell ever since he was sentenced last December, commenting on current events and launching diatribes against Hosni and Gamal Mubarak -- among others. The column is quite important in keeping Nour in the public eye, as well as inspiring the rank-and-file Ghad members, while he is incarcerated. By doing this (presumably illegally, as I don't see why writing from jail would be illegal), the regime is hoping to further constrain Nour's ability to lead his party and have a wider influence on the Egyptian opposition.
You may remember that new charges have been brought against Nour in addition to the previous trial (which being appealed) and that prison visits were made more difficult after a Al Masri Al Youm journalist snuck in to interview him. Another thing I'm hearing is that visiting US officials have asked to visit Nour in jail, but I'm not sure whether their requests were granted.