I would like to create a web application that will allow automatic scheduling of messages on social networks. I managed with twitter, facebook will not ask me a problem but I also want to do it on linkedin and Google +
On the husbpot documentation it talks that of facebook and twitter with the API: http://developers.hubspot.com/docs/methods/social_media/create_broadcast
Messages can be created for any social media account that has been connected to HubSpot. You’d need to look at all of the publishing channels to see what accounts are actually connected:
GET /broadcast/v1/channels/setting/publish/current - Get details on the channels (e.g. Twitter account, Facebook page) connected to this portal that can be published to.
A "channel" is a specific destination like a Twitter profile, Facebook Page or...