You'd also want to limit it to the most vetted and monitored articles to prevent someone from the outside from leaving coded messages in articles. I figure the more popular articles could spot strange updates and eliminate them.
There's also nothing urgent about the access they get. Articles could be restricted to 1 or 2 years old to further prevent the transfer of timely information.
Honestly, is this really that big of a concern? This sounds like something that may be necessary for the OBLs or <murderous drug lord>s of the world. But in general, this level of paranoia about being able to communicate with the outside world is just insane. It only serves as an easy excuse to exert an obscene level of control over these people's lives.
From what I've seen (in documentaries and the show lockup raw) violent offenders will try to harm the families of prison personnel and others by sending and receiving orders. It's a real problem. It's not as easy as restricting access from just these people because they can force other inmates with Internet access to do their bidding.
Its possible that lower security prisoners can be treated differently.
Sure, the process in my mind is the same as when they are given a TV. There is some level of filtering on what information they can obtain and a time delay of when they obtain it. Regardless there is so much information out there that even if you drop entire categories from a Wikipedia dump, it would still be left with a substantial ammount of knowledge for inmates to learn from.
Isn't worrying about coded info coming into the prison a bit silly, given that inmates have visiting rights? What kind of code could you put into a wikipedia article that you couldn't provide in a face-to-face?