Why doesn't my jailbroken iPhone work like a regular iPhone?

I was waiting for something like this to come up with the unlocked/jailbroken iPhones. I remember reading an article a year or two ago about hacking Time Machine to do network backups before it was allowed, and the author basically saying "here is the theory behind what you have to do, so if you know what you are doing, go right ahead and proceed with caution." Basically saying, I've given you enough rope, it is up to you to hang yourself. In a follow up, he said he was inundated with requests for a step-by-step description of the hack, but as he stated in the original article and reiterated then, he wasn't going to do it because he did not want to be responsible for broken backups, which would happen frequently if there was a network hiccup during backup. Instead, he had published information which would allow someone to replicate his hack if they knew a little bit about how the system works, hoping that if they knew how the system works, they would also know why modifying the system would be a bad idea and what the consequences may be -- in this case, broken backups.

So let's go back to the "hacktivated" iPhones. Step-by-step descriptions of modifying your iPhone exist on the web and are relatively easy to find. What is not necessary to follow these instructions are an intimate knowledge of how the hack works and what it might be affecting. The story linked above illustrates that hacking your phone may have consequences beyond being able to run unauthorized programs or use it on a non-sanctioned network, it may break core functionality of the phone. If you hack your phone, please be responsible enough to own up to it and not blame someone else for breaking your phone. You broke your own phone when you hacked it.

Update: So the plot thickens. Now users who hacked their iPhones are getting each other's push notifications.