Comodo does much more than the built-in option in Windows. As it should, it blocks attacks from outside, and it has a malware detector that's better than some antivirus systems. It also installs the Comodo Dragon hardened security web browser. (Be careful during install, though; nice as it is, it may try to change your browser home page and search engine defaults.)
Google built Hangouts into its services as a replacement for the Google Talk messaging service, but Hangouts adds voice and video calls. It's unique for this roundup in that it doesn't require an installer, it just works in your browser (though getting the Chrome Extension is recommended). It's perfect for talking to other people on Google—you can get up to nine people in a video chat, all for free.
The freedom to redistribute copies must include binary or executable forms of the program, as well as source code, for both modified and unmodified versions. (Distributing programs in runnable form is necessary for conveniently installable free operating systems.) It is OK if there is no way to produce a binary or executable form for a certain program (since some languages don't support that feature), but you must have the freedom to redistribute such forms should you find or develop a way to make them.
^ Barton P. Miller; Gregory Cooksey; Fredrick Moore (20 July 2006). "An Empirical Study of the Robustness of MacOS Applications Using Random Testing" (PDF). Madison, WI 53706-1685 USA: University of Wisconsin: Computer Sciences Department: 1, 2. Archived from the original (pdf) on 21 June 2010. Retrieved 1 May 2013. We are back again, this time testing... Apple’s Mac OS X. [...] While the results were reasonable, we were disappointed to find that the reliability was no better than that of the Linux/GNU tools tested in 1995. We were less sure what to expect when testing the GUI- based applications; the results turned out worse than we expected.