The difference between Sexting and SextCasting is very simple to explain. Sexting is simply a type or method of SextCasting.
A SextCast or SextCasting is a term defined by The Institute for Responsible Online and Cell-Phone Communication as the process by which an individual(s) performs actions of a risqué or sexually explicit nature via a (live) webcam (or webcast), digital (image or video) camera, or other form of digital technology (e.g. a cell phone) and sends and/or saves the content of their actions using digital technologies (i.e. a computer, camera card, email, social website, message board, etc).
From a consequence standpoint, an incident of sextcasting in the form of sexting (as opposed to a live webcam feed or posting a video to a site like YouTube), is easier to contain as law enforcement can insist that anyone who has received the image on their phone delete it or face penalties. Once an image, video, or webcam feed (sextcast) is posted online, in other words, somewhere on the internet and not isolated to cell phones the sextcast can instantly become viral and virtually impossible to contain.
For more information about sextcasting, please do not hesitate to contact The Institute for Responsible Online and Cell-Phone Communication.