This is at the moment only an idea.
With Launchpad we are having a mighty tool for the development and maintainance of Ubuntu. But I think we could go one step further. What about an API to allow other Ubuntu related sites to access stuff from Launchpad?
Case study: At the moment on ubuntu-de.org a programme to upload hardware data is programmed by mitsuhiko (backend) and myself (frontend). The idea is to upload the hardware data of users pcs (multiple pcs possible) to our website and use them for troubleshooting. If a user has a problem for example with his graphics card, he simply uploads his harware data and the community can take a look it to find out whether the graphics is supported or not or if it for instance IRQ malfunction. It's a nice tool. But it would be better if we had some central account to upload stuff to. What if we can't help him. Perhaps the ubuntu-forums.org community can. We have the hardware info, they don't.
The idea is: the users creates one account in the ubuntu launchpad. If he now wants to register at ubuntu-de.org he can choose between creating a normal account or to authenticate via Launchpad. If the user chose to use the Launchpad login, the website will forward to the Launchpad site. There user enters his password. After that the user can allow the other website to use the launchpad login (you guys know paypal?). Then Launchpad takes the user back to ubuntu-de.org. If the user now wants to upload hardware data, he uses the tools coming with Ubuntu.System->Help->Online-Support->Upload Hardware Data. All pages the user is registered on will be able to show the information in the websites language.
It's just a very rough outline.