What is a Non-Disclosure Agreement (NDA) and should I sign one?

[Btaliat]

It is a better thing to make sure that you have NDA, Non-disclosure Acts. With this, your clients can easily trust you that you cannot disclose information that is very sensitive. The act is also called confidential acts which exists between the two parties making sure that they sign the contracts. There are some situations where freelancers may be too slack with sensitive information, clients can use this against him as well. What do you think about this?