Exposure to inappropriate or offensive imagery, objectionable language and generally lewd behavior are all likely risks of using Chatroulette. An attack through Chatroulette's servers on your computer, on the other hand, is not very likely. However, hackers could potentially find your IP address when you use Chatroulette and could try to lead you to a site that will attack your computer.
You are not fundamentally vulnerable to an attack through Chatroulette's website. Any website could infect your computer with malicious code if a hacker penetrates its server undetected, but Chatroulette is not more vulnerable to an attack than any other website. The process of displaying a video from another user's webcam in your browser's window is not invasive into your system, so any user you connect with cannot directly hack into your computer through Chatroulette.
Chatroulette may not collect information like your name or email address, but it does let people discover your IP address if you are using the site. With this information, a hacker can attempt to connect directly to your home network and begin probing it for weaknesses he could exploit. Consequently, a hacker could use your Chatroulette activity to get the information he can use to try and attack you, but he cannot attack you directly through the site itself.
Chatroulette secures its own website servers from malicious code, but hackers can maintain their own websites loaded with malware. They can't force you to visit their sites by triggering the attacks on your computer the hackers programmed the Web pages to execute, but they can try to trick you into visiting them through Chatroulette. In the course of a Chatroulette conversation, a hacker could send you a link and describe it as something in which you expressed interest. However, if you opened it, you could find yourself at a website trying to infect your computer with malware.
Anyone you chat with on Chatroulette does not have to hack your computer to record your entire conversation. Anything you do or say could end up on digital video, which could find its way onto any number of video sharing websites. For this reason, you shouldn't put your trust in Chatroulette's anonymity when it comes to doing things you would not want captured on video and shared with the entire Internet.