These guys may not be living next door to you today OldRedCap but they probably don't live that far away. You can be sure that the more extreme blogs and websites will not get as much media exposure as those that are more palatable to the current political 'message'.
As usual, it's the young firebrands in the West that are radicalised. They are more technology and media savvy and able to spread the word more effectively as well as being more hormonally susceptable. You don't see the elderly imams in the front line over here, they just wind the young ones up and point 'em in the right direction.
Islamic culture has very little in common with modern western civilisation or thinking. Those who do manage to integrate to some degree certainly keep very quiet and have no intention of trying to influence their more extreme brethren. So I am sure that we will see more of this sort iof thing in the future. We just have to get used to it.