A webinar is best described as a seminar that takes place online. Apart from the fact that you are not physically in the same room as the lector and other participants, it is the same.
With the use of a web application you can watch the lector’s presentation and listen to his lecture. You can ask him questions, express agreement / disagreement, vote etc. All you need is a computer (or a smart device), microphone and internet connection (webcam is optional).
The main benefit of a webinar lies in the minimization of costs. You don’t have to take a trip to where the seminar takes place which would cost time. A regular seminar will surely cost more, because the organizer has to rent the premises for it. And finally – there is no place like home. You can experience everything as you would on a regular seminar, but in the comfort of your home.