I am loving WallWisher which is an incredibly easy tool to use for online communication and participation. Its free...you don't have to download anything...and you don't need to have an account.
You can use it as a personal online pin or notice board, or you can use it as a group message board or way to get feedback from people.
Here is a WallWisher I made to find out what people think about online facilitation. - feel free to leave a comment or 'sticky'.