Nullwatch

Nulled scripts are those applications for the web or desktop that have been modified by pirates in order to bypass security measure that prevent from installing, distributing, etc.

These people often add malicious code to your application compromising your application reputation.

If your application becomes succesful, there are many chances for it to become nulled.

You should allways monitor for copies of your script s in the pirate scene to find vulnerabilites and other important info.

Nulled scripts are oftenly for developers the first approach to some applications, there are tons of people who try nulled scripts and buy them. But these are minimal, allmost allways developers that use nulled scripts get away with it and leave the software online.

These is probably the easiest way to tryout different applications when in search for a solution on a project, or perhaps to tryout some new very expensive software which is impossible to buy. 

For small companies that depend on certain software for their survival, these is one of the worst scenarios. Let's take the case of vBulletin, it is on the most pirated web applications, there are tons of forums for people releasing the latest versions, addons and themes, people usually don't take for notice when they use a software, but let's face it. It's stealing.