State prisons vary where some don't care at all so long as you don't specifically call out guards by name, you're free to keep a blog and even criticize the warden but BOP, this is a big no.
There's some outliers to that article, many state prisons allow for min wage now such as Arizona where female inmates can work at a polling/telemarketing company and be paid the state minimum wage. The great thing about this is those inmates walk out with $10,000 or so saved up and have a chance to land on their feet instead of say, TDCJ who denies state prisoners any kind of income whatsoever.