You can link out. But one of the things I like about Kindles for reference books is the ability to use it where you are, and not have to have an internet connection in order for it to be useful. Also, Silk isn't that great of a browser.

A bit off-topic, but I couldn't get at all interested in Kindles until the Kindle Fire, because that was the first time it would render O'Reilly books correctly, or render something like a resistor color code correctly. I love having a programmer's reference library in my laptop bag.