Comment 76 for bug 361205

as a general rule I'd say leave the testing releases of Ubuntu itself to the experts, unless you have a spare machine kicking about -- but for testing individual packages, esp where the existing package is a real show-stopper (like this one) you can judge how dangerous it might be when you try to remove the package that is causing the problems. In this case, removing the tracker package only involves a few other packages that all have 'tracker' in the name, so they are highly unlikely to cause any upset. On the other hand, if you tried to remove some package and discovered it wanted to take a dozen packages with it, and especially if many are general-use lib* packages, I'd say again, best leave it to the experts ;)

As for how to do this: the link Chris gave to the PPA contains full instructions, but what is maybe not clear is that you have to click on that odd hexadecimal key number and follow the links to get to his public key, then save that to a text file and install it in the package manager according to the instructions.