A method includes performing operations as follows on a processor: receiving a selection of a content item by a first user from a first mobile device, sending an inquiry to the first mobile device comprising collaboration options for the content item, the collaboration options comprising a first option to invite a second user to collaborate asynchronously on the content item and a second option to invite the second user to collaborate synchronously on the content item via a communication session between the first mobile device and a second mobile device associated with the second user, receiving a selection of one of the first option and the second option by the first user from the first mobile device, identifying an address of the second mobile device responsive to receiving the selection of one of the first option and the second option, and sending a message addressed to the address of the second mobile device.