The origin of the name is said to have originated with a reply of a Montreal fast food restaurateur who said, when the customer asked that cheese curds be added to an order of chips 'n gravy:
“ça va faire une maudite poutine”
The term "une maudite poutine” was Quebec slang for "a damned mess'. The term caught on and the rest is history.
As you can see from the following picture, condiments can be added, such as ketchup, but I prefer it in its original form.
Canadian grocery stores sell packets of poutine gravy mis which is essentially brown gravy lightly spiced.
MacDonalds in Canada serves what it calls "poutine" but I found it to be too bland for my taste. This is a cultural variance, no doubt, such as, for example, the Yank manner of serving tea. I have learned to specify, when ordering tea, that the tea bag be put in first and that the water be at a full rolling boil, otherwise I would get lukewarm weak tea. I think that this may have something to do with Boston Harbour.