Norton has been blocking access to links with its 'Norton Internet Security'. Why it thinks this makes you more secure, I don't know. Its shipping on a lot of new computers with the default setting to 'on'. I think what it is doing is making it so you can only visit companies they approve of.
I don't know if companies pay money to get their links unblocked or to stay off the blocked list.
If editing your .hosts file didn't work you might want to try deleting Norton and using something else.
Sorry, I didn't see this last page of messages till after I posted!