Education users
Professors, students and teachers are free to use it in classroom presentations and demos, dissertations and other non-commercial academic works, researches and all related not-for-profit activities. The use of our files is still bound by a license but its use is completely free as long as:
(1) the downloaded image is used according to its terms and conditions;
(2) humanline.com is accredited as the source by a credit line or an active link to our website; and
(3) it is not distributed to third parties.
via http://www.freetech4teachers.com/2012/04/humanline-thousands-of-historic-images.html
Calendar app which lets you send colleagues/friends available dates for planning, parties, events and each person can choose which dates work for them.