You mean annonimous security related data of infection, malware and clean executables... Hmmm... Do you really think there is a privacy issue on that?
You can read the privacy policy but, after all, if you don't trust your security vendor (and I'm an avast! user for the last 10 years...) you shouldn't use its program at all. avast! is not a company that need personal user information and respect your fully privacy.