Because this is a third-party app that uses your Google account authentication, you'll need to grant access to it by clicking the "Login" button.
This is a sample that demonstrates combining the Gdata JavaScript Client Library with Google Gears to create a Blogger app that can still be used offline. If you'd just like to see how to create a Blogger app without offline capability, check out this example instead. If you'd like to use this app but do not have Gears installed yet, get it here.
If you're interested in how this sample works, you can read through the code and comments in bloggears.js. You can also check out the short slideset describing the functionality. The image below is from those slides.
