Webinars , Unified Web conference plateform are designed for smaller groups, from meeting-sized groups to online events involving 5 to 25 of people. They often include many of the options available with online meetings, such as Q&A, polls, whiteboard and markup abilities. So webinars are full-featured presentations or events for a few 10-25 or (often) far fewer 2-5 individuals.
Webcasts : These are primarily with video and slides or video-only and are based on a video-to-user model. In other words, they’re more like a event show (possibly live) than a meeting. Large webcasts can handle hundreds or even of thousands of viewers. So webcasts are audiovisual experiences aimed at larger audiences, with the trade-off being fewer options for the end users.
Video streaming is the delivery of video and audio over the web. Video files are accessed via a link on a web page. on other side Playback is through an ordinary PC, laptop, computer or mobile phones without videotapes or DVDs etc..
Video Streaming save your time, no need to wait for a long to complete the event and downloading first archived video from portal. The user can start watching the file almost as soon as event happended live on site.