The technologies introduced below either don’t require accounts, or are non-for-profit - except Polldaddy.
Padlet accepts many media from many contributors, and displays these cleverly in a page which can be exported in PDF, spreadsheet and other formats. Padlets can be embedded and it is possible to receive alerts of changes.
Developed at Northwestern University, Gigapixel lets people annotate high definition images (you need to find somewhere to host these).
Developed in the University of Minnesota, a free service for minute-by-minute annotation of video uploaded to YouTube.
Students can interact with your slides using their own devices connected to Eduroam. Question types you can use are multichoice, short answer, ranking and click-on-image.
Polldaddy lets anyone with a wordpress.com account set up polls or surveys. It allows unlimited responses (this is rare, and what makes it amenable to large groups).
Zeemaps is good for mapping markers, routes, boundaries, landmarks, destinations, or objects.
Jane Hart's annual Top 100 Tools for learning: http://c4lpt.co.uk/top100tools/
Alan Liu's Digital Humanities tool chest http://goo.gl/0YHLGQ