I think clickbank is the greatest affiliate network now but there are a lot of networks like cj or amazon else. you can choose as you like.
Yes but only in English because it is produced despite French, it is far exceeded by many other much more simple ...
Is it the best? For some and not for others. I think to do good with CB, you need to market ebooks a certain way to get the best ROI. The refunds and other things that go along with CB products can make it tough sometimes. I like adding some relevant products from CB on my sites, but also adding relevant offers from other affiliate programs as well. You'll have to experiment. Now, creating CB landing pages and review (comparison) mini sites about just one specific niche, can do quite well with the right amount of targeted traffic. good luck!