I posted the other day about a Visual Studio add-in which I developed. When developing it, I used the add-in model which has a nasty side effect, it needs to be installed with a MSI. Visual Studio 2010 can also be extended with packages and these can be deployed using the VSIX format.
What is this magical new VSIX format? It is basically a ZIP file which contains everything you need plus a manifest which tells VS how to use it. What makes this much better is that VS handles the install itself, so no MSI is needed. It is also then listed in the Extension Manager and so can take advantage of the features there by being disabled/uninstalled easily, not that you would want to.
A great side effect of this is that the new extension model let me add a little more error handling to the tool to help out debugging it. To get the new version go to http://findresultstweak.codeplex.com