My experience watching Avast Free is that it definitely attempts to send out data. I doubt you will find an antivirus product that does not, free or paid. The data is there to take and they will try and take it. Judging from the postings on this forum, people trust their antivirus software, some to the extreme. I see no basis for this trust. The only safe way to use AV software is to firewall it from connecting out, like you would any other software (I hope). Updates to the virus definition files can be installed manually.