Legal documents such as Vendor Agreement, Co-founders agreement, Consultant contractwebsite usage contract etc are documents that define scope of engagemnet, rights and obligations of parties signing the contract. It is important to have full understanding about the implications of the listed terms before signing the document and binding yourself by the contract. Make sure you get the important legal documents reviewed by professionals who can save you from possibly infavourable clauses and suggest you recommended changes to help you save your interest.