Over the last few days, we've introduced several improvements to the sandbox to help flesh out what the full social experience will look like for your users.
First, sharing a gadget is a richer experience — requestShareApp invites now display notifications at the top of the invitee's iGoogle page and in the "gadget shares" link on the left nav bar. This system smoothly handles all the different use cases for you. If you invite a friend who does not yet use iGoogle, they will receive an email inviting them to join iGoogle and to share the gadget with you. Then, if your friend creates an account they will be prompted to add you as a friend. If your friend already has iGoogle but does not have you listed as a friend and/or does not have the gadget, they will see one of the new social notifications prompting them to add the gadget and/or to add you as a friend, respectively. Finally if the friend you invited already has you as a friend and the gadget, they'll get a dismissable message saying that you have invited them. As a developer you won't have to worry at all about whether or not someone uses iGoogle, has the gadget, or is friends with the user — requestShareApp will handle that all transparently for you!
Next, you can delete the "Sandbox Friends" gadget, because our real control for editing and expanding your friends list is here, living in the "Friends" link on the left hand nav bar. This, in addition to the prompts described above, is how users will add friends to their accounts.
And finally, the Updates gadget continues to improve — multimedia Updates should be displaying much more cleanly now, and you can also filter Updates for those posted by your own gadgets. Remember that the final version of Updates, like the friends control and social notifications will live on the left nav bar, and gadgets will be limited to three Updates per user per day.