Aza has a nice post describing the latest spec for the new tab page in Firefox 3.1. For some additional background, read the concept post.
The basic idea is to put some useful content into the (currently blank) screen that appears when you open a new tab. Since users frequently open new tabs to do something with text they just copied (search, map an address, define a word), why not add actions to the new tab page based on what the user selected in the previous tab. Here’s Aza’s example:
This is pretty good, but you still have to actually click to get the data you want. As Aza puts it, “Don’t force the user to ask for more content: just give it to them”. In other words, don’t make the user click “Map 3312 Main Street, Pacifica”; just put the map right in the new tab page:
A map this small might not always be useful (though in real life you could probably make it a bit bigger), but the user can always click it to view the whole thing. Maps are also a particularly tough case — you’re almost always going to be able to fit a complete definition or translation on the new tab page.
Now, one potential downside to this proposal is speed. The new tab page has to load instantaneously, and you pay a performance penalty if you have to look up a map every time you load it. If the user isn’t interested in a map (i.e., he just happened to have mappable text selected), he’s not going to be willing to wait.
However, there’s no reason this extra content must load synchronously. The new tab page could load its basic content first (the links in Aza’s mockup), and then get the richer content in the background once the user can already interact with it. This means you’d have to put a little throbber in each button while the content was loading:
And the user might have to wait a second or two to see it, but this is still much better than having to click. Furthermore, if the user isn’t interested in the additional content, its loading won’t disrupt his experience.