My popplet invitation arrived today, and this is my first effort. It is extremely easy to use and can be used for visualisations and mind mapping. Flickr and Facebook photos and Youtube videos can be inserted into the popples (idea or word bubbles) and links between popples can be drawn.
Popplet is in beta release and i had to wait a few days for my access code to arrive, although a friend had sent me an invitation I don’t recall seeing an invitation, but when I tried to use the access code I had to use another email address.
If the embed doesn’t work (it’s an embed script) use this link to take a look.