My experiment with Snap Preview lasted for four days. I agree with the comments back on the original post. This is functionallity that belongs to the browser. And on recommendation from Onno I have installed Cooliris. A plugin for Firefox, Safari and Explorer that I now can recommend as well. It gives you a quick preview for links in a popup window. If you like what you see you can quickly transfer that page to a new tab.
You get a small blue square besides the links. When you mouse over the square a popup will show the page. I have made a quick screen recording to show how it works.
Link to video.
The screen recording was made with the free and open source tool called CamStudio. Currently windows only, but if you’re on Mac or Linux you can find different tools for screen recording in this list in Wikipedia.