There are lots of dangers online. Hackers are a very serious problem, since they can access personal information by breaking through your defences.
A post on http://www.bgr.com/2011/08/01/lulzsec-hacker-jack-davis-aka-topiary-released-on-bail/#disqus_thread>www.bgr.com says that a hacker called Jack Davis (a.k.a Topiary), known as the 'face of LulzSec' was behind several online assualts and was charged with hacking the Sun, the Times, Sony and the Serious Organized Crime Agency.