Outside of getting books off whispernet Wikipedia works and that's it. Not really worth my paying extra for the 3G at all. Read the fine print, I should have. I know dealing with mobile carriers is a complete nightmare but Amazon is very crafty in calling the browser "experimental" and burying the information about browsing deep in their pages (I looked hard for it on purchase but only found it on the page now looking again).
All that said, if the browser is there you will probably get distracted. They could easily add tons of features to it but that would move it away from being a single purpose device. The more features are added to the Kindle the less you will see people raving about it. Kindle will have trouble selling against a colour e-ink device with some kind of android that's been modded for that type of screen at the same price point. I suspect what will happen is that features will stay largely the same but the price of the kindle will dive down amazingly. Thus you will see a kindle 4 and kindle 5 wifi for $80 then $50. Perhaps university editions, branded to particular universities, will gain the colour e-ink, a more advanced browser and more features like email and push the collaborative/community features more as there is compulsion connected to that reading. But for just reading, getting the device as cheap as possible and into as many hands as possible is a better option for them than adding distractions.