Maybe someone could answer this for me, this discussion made me curious:

I have an old (2005) Mac, and my fav browser on it can't show https sites at all 90%+ of the time - "Cannot Load, Secure Connection Failed". (like the usual https sites linked to in HN stories) But it works fine with some https sites, e.g. github https, youtube, this page.

What is it about those 'working' https sites that makes them different? Hopefully that's enough info to answer that.