Nowadays a lot of US sites offer money for giving surveys. Is it Haraam or Halaal to earn money by giving surveys? Also is it proper to sell e-books online? I ask this because e-books can be sold in online format many times without buying them? In Islam is it compulsory to buy things before selling?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

In general these surveys contain some religious prohibitions like the following:

1)      The Muslim will be committed to some sites that are forbidden because of the temptation and attractions that they contain.

2)      The Muslim will participate in things that are not permissible for him to participate in, like choosing the best singers and other dissolute people.

3)      If participating in such a survey is in return for money, then this is paying money [even if it is a small amount] for people to participate in it [therefore it is not permissible].

Therefore, we consider, and Allaah knows best, that it is more appropriate for a Muslim to be careful about earning money in this way, in order to be safe in his religion, honour and dignity. This is in relation to the first part of your question.

As regards the second part of the question, the answer is that the custom dictates that the right of innovation is a particular property of its owner. The majority of scholars gave the Fatwa that it is not permissible to abuse this right without a prior permission from their owner. If the business owners state that the copyrights are reserved or state that it is permissible to benefit from it but not sell it, then this condition has to be met. However, if they do not state any of this, then it becomes permissible to benefit from it by any lawful means, like selling and the like.          

Allaah knows best.