It's problematic that most countries immigration websites don't explicitly point out that working for a company abroad or for yourself is not permitted on visitor visas, but if you write to their respective embassies then you will find this to be the case.
'"Work" is defined in the Regulations as an activity for which wages are paid or commission is earned'
On another Canadian immigration page:
"Most visitors to Canada cannot work or study in Canada without a permit."
http://www.cic.gc.ca/english/visit/extend-stay.asp
It's problematic that most countries immigration websites don't explicitly point out that working for a company abroad or for yourself is not permitted on visitor visas, but if you write to their respective embassies then you will find this to be the case.