There is a commenter popping up on some blogs who calls himself "Jonathan" and sometimes "Tom Robinson" and maybe other aliases as well for all I know.
This individual is threatening and advocating violence against people he doesn't agree with.
The IP address of at least one of the posts by this person is 18.104.22.168
That shows up as being assigned to Cogeco Cable and is located in Welland, Ontario .
If there are other IP addresses associated with this individual it is likely the result of dynamic IP assignments rather than static.
At any rate, all incidents of commentary by this individual (or any other individual for that matter) either threatening or advocating violence of any kind should be immediately referred to your local police department, your local Crown Council office (for assurance and proof) and/or the RCMP, OPP, or QPP.
Each time you receive a threat you should also use the tool I linked to above and identify the location of the IP. If it is in your town call the authorities at once with no delay at all.
Unbalanced people should not be humoured. (Thanks for the catch Noni)