My second grade team began using it on a trial basis but now we each have a subscription. We are now able to collaboratively plan online and it is amazing. The site allows us to access each others plan books and share information. We can also hyperlink websites, upload files, make notes, and carry the lessons over to next year if we choose. We have one team member who inputs all the reading plans and then we go to her plan book and transfer it to ours. We do this for all the subjects, and we even have a team member in charge of putting in important dates and reminders. Our curriculum requires integration across the board from the classroom to physical education. Through Planbook.com we have given the specialist teachers and administration who are unable to attend our team meetings access to our team leader's Planbook.com. This way the specialists and administration are able to know what is going on in our class and discuss any concerns or ideas they may have to improve instruction.
The biggest challenge we ran into was team members who were reluctant to change. They were concerned about the time it would take and the effectiveness. In order for something like this to work everyone must be on board. Luckily, after our short trail basis we all love it and are all in!!!