I am interested in watching an upcoming webinar that will discuss Puppet on AWS. In order to participate one needs to install a software application. Naturally, I won't do that as I can find enough information about the subject with a few simple Google services.
However, sometimes there are webinars that I am interested in participating in. What criteria might an average user use to decide if a software package seems safe enough to install. Though Firefox is open source, I'm satisfied enough to trust the Mozilla binaries and I couldn't review all the source alone even if I weren't willing to trust the binaries. So that is a lower limit of what I'll install. What would be reasonable criteria for establishing a reasonable upper limit?
Of course, I'm not looking for 100% security as nobody can provide that. I'm looking for something reasonable for average users who are not software developers. The computer is useless without installing third-party applications, even if the OS provided them via a repo.