What is comission junction?

Hello, I know those kinds of threads are very annoying and I could search to find an answer but I don't really understand, is it like ClickBank? like is there many products and you choose one to promote? If yes are they digital products or concrete ones?

They are an affiliate network, you apply to companies to promote their products. CJ handle everything. Why didn't you use Google?
http://www.cj.com/about-cj

Yes they are an affiliate network just like clickbank. I believe there are both digital and physical goods. You can find lots of big name vendors there, like Disney and Hostgator. The main difference between them and clickbank is that you don't get auto-approved for every product, they are more strict with promotion (you can see each vendors' rules before applying) and their payment schedule is approximately two months after you have made the sales.