Cisco Exam 700-070 Topic 1 Question 3 Discussion

On an IX-to-IX point-to-point conference, you can share up to two presentation streams - for example, one presentation content source and one whiteboard source. If hosting a meeting locally with no videoconferencing, you can share up to three presentation streams.

http://www.cisco.com/c/en/us/td/docs/telepresence/ix_sw/8_x/admin/guide/ix_8_admin_guide/ix_s w_features.html