What things can be copyrighted of a startup before approaching VCs? I have a very fast growing online venture for which I am going to approach VCs. But I want to make sure they can't use my idea and marketing strategy if they decline investing in me. Can my idea and marketing strategy be copyrighted or considered as intellactual property?
What you are talking about it Intellectual Property protection (of which copyright is one strategy.)
You have several options:
The point is, that it is really difficult to protect an idea unless you control some kind of rare resource which is vital for the implementation of the business.
You are asking an extremely broad question, while giving us almost no information about your "online venture". The question as you pose it, is impossible to answer.
I will say this though. VC's invest in people, not ideas. If you have no hope of making the most of your idea, it will be stolen. Some way, some how. If you are the best person with the best team for the job, you are safe no matter what. That is your best protection.