I also like the level of communication from the lisek229. It is refreshing to see this energy and commitment to answering concerns of those interested.
So, to discuss further, the issue of legality is not so much the use of the word, "face". The issues go more into brand recognition and symbolism. For example, the avatar being used by lisek229 clearly uses the Facebook icon which would be argued by those in the Facebook camp as copyright infringement on grounds of brand recognition.
edit, here's more on that:
http://www.hivestrategies.com/2011/05/honoring-copyright-part-2-legal-ways-to-use-common-social-media-platform-logos/"Dont: Manipulate the logo in any way."