Actually I dont have idea about this website but my friend said that here we can learn any course we want and get a certificate by writing the exam conducted by Nptel we will get certificate from IIT where ever we want its really wonderful right? ofcourse it is really and now I am studying COA( computer organisation and architecture) I enrolled for this course they will keep every week 5 videos like that depend on course they will keep week for example COA is 5 week course which is 5 videos per week and per video it will be 30 mintues and the teachers those who says the lessons are IIT professors and I suggest you to take the course what ever you want in this website it is really helpful you to learn the subjects but if you want certifictae you need to pay some fee for the exam or else if you want to learn for free you can llearn when ever you have free time you can go through the website and learn through videos
and my rating for this website is 4.3/5 every student can go through this using gmail account
