Hey Jayne- just a few thoughts for you on this post.
Firstly, if this was meant to be a post, it would be better if you'd explained the service first rather than just sharing the link. And why you think it's a good idea.
Secondly, if this is an advertisement, it isn't allowed as per the GOOD terms and conditions. FYI: "You must not upload, post, email, transmit or otherwise make available any unsolicited or unauthorized advertising, promotional materials, "junk mail," "spam," "chain letters," "pyramid schemes," "affiliate links," or any other form of solicitation."
In regards to the service, IMO schools are already connected through diaries, emails, meetings and newsletters. Personally, I don't see how 'chalkup' actually helps streamline these, as the methods used to connect everyone don't require the internet to make them work. Shouldn't we be relying on the internet and technology less when it comes to youth learning and development?