Echo'ing a number of comments...

Internet cafes in port are the better value. They are the more logical choice if you want to do stuff that need a constant connection (IM, surfing that requires a lot of linking or entering data, etc). Security is a consideration too. It's kind of hit or miss whether or not one wants to or can spare the time in port to visit one.

Internet onboard ships is pretty pricey but there are many ways to limit your live connection time so that it's effective for activities that don't need a constant connection. Compose one's email offline in Word (or whatever) and copy & paste when connected. (I suppose one has to do the reverse if they're using webmail versus a mail client.) For news, I connect to my local newspaper online, cnn, news.google.ca, finance.google.ca, etc and scan the headlines. For any article I think I'll want to read, I just click on the link while holding the CTRL key to open it up in another tab in the browser. I can then disconnect and read the articles offline.

I think I purchased a 90min package on my cruise and was hard pressed to work thru that time over seven days. And I consider myself an Internet junkie.