Having made a lot of use of internet cafes in Shanghai I'll add my $.02 here:

I can't comment on how many disappeared in the crackdown, every one I knew the location of survived.

The cafe I use charges between 2 and 4 RMB per hour depending on the time of day and what machines you use. The lower quality ones are 2 in the morning, 3 otherwise and the better ones are a RMB more.

Connecting your own laptop to the equipment is definitely illegal--you don't have the monitoring software on your machine.

However, even post crackdown I routinely used my laptop at the local cafe. I needed to throw files back and forth with home, there was no other way to do it (and I much preferred it anyway--their systems were so riddled with garbage that the mean time to crash was maybe 90 minutes. Not to mention the ad zapper that decided the moderator tools menu of a board I help moderate was an ad.) They understood the problem and permitted it. Even the cops understood--I saw an argument between a couple of cops and the clerk once. While I couldn't understand a word it was obvious what the issue was--and it obviously ended up with the clerk convincing them that I was harmless.

The cafe is now under new ownership, better machines and the good ones have a USB extension cable dangling on the desk--you can plug your flash drive in. Connecting my own is now not permitted but the way the billing system now works they couldn't handle it very well anyway. You buy a prepaid card and use it to log into the machine--when you leave they credit back whatever's left on it. I believe you can also just log off and take your card and bring it back next time but I do not know for sure. (The old place you simply got a number card when you entered and when you left you turned it in and paid for however long you had had it.)