You should say:
Why is it your favorite website?
How often do you use it?
What would your life be without it?
My favorite website is youtube.com. A lot of people in this world regard YouTube to be their favorite website and I feel in the similar way. This is a website in which a person can watch or upload videos for free, and the great part is that the user can even create his or her channel and then earn money by the by the videos he or she has uploaded. We can find almost everything on YouTube and everything is available over there free of charge.
I started using YouTube 4 years ago and it has been a really great experience. I spend most of my time on YouTube. I have to upload my own video lectures on YouTube and these video lectures are provided to the people for free. I also stay on YouTube to watch trailers and songs. You can find almost every song of this world on YouTube. There was a day when I missed a cricket match because I was busy in something, but because of YouTube I was able to watch the entire math again because someone had uploaded the match and it made me very happy.
My life would be hell without YouTube. I would not be able to function without it. I am running an educational institute in Pakistan, and I provide free online video lectures to everyone irrespective of the fact that they are my students or not. If YouTube goes out of my life I would not be able to provide this free service and it would be bad not only for me, but also for all the people who are benefitting from it.