The biggest danger is to former Windows users who are used to hunting for
applications, downloading an exe that is of dubious value and quality from
an unknown source. Bringing such habits to Linux is a recipe for disaster in
many ways. But in the end, you cannot protect users from themselves.

They are the weak link. This applies to Windows as well as Linux. I have a
computer graphic that is a play on "Intel inside" and it says "Idiot
Outside". Computers only do what we ask them to do. There are weaknesses in
Windows and in Linux that can be exploited, but we must play our part to get
infected. There is no substitute for good common sense. Linux is set up to
protect us from our own stupidity. Windows facilitates stupidity, but that
is changing, .. slowly.

It is one of the main reasons for killing off XP. Google recently scrapped
Windows corporation wide. They are not the only company either. Many
countries recommend against using Internet Explorer and some, mostly in
Europe, are moving away from Windows altogether. Microsoft itself is urging
XP users to move to Windows 7, not just to make money, but because it is a
security risk to everyone. Law enforcement agencies point to botnets that
are made of XP computers that have been compromised as problems worldwide.
Nobody should use XP to do anything online, IMO.

Users need to decide what is the best replacement. I made that decision for
Linux almost ten years ago and have never regretted it. I would not even
want a free copy of Windows 7. It is just too high maintenance and not worth
my time.