Hey, Angie! There is a discussion about AddThis here that might be worth checking out. One thing that makes it difficult to have Ning Networks appear on that link-sharing service's list of places to share is that each network on Ning is a separate entity, so content that is shared wouldn't appear across all Ning Networks. Basically, Ning doesn't publish content across all Ning Networks but instead lets Network Creators control what content appears on their own individual network. But, I would encourage you to try out their service and embed it on your network if you're looking to broadcast out to more places online.
from a mistake i placed something like that to the advance section of design studio and now the studio its not loading .
Be very careful, you can add it to a box i guess .