http://forums.ebay.ca/thread.jspa?threadID=300019585&tstart=0&mod=1124730129027
The short answer is "anything paper, or having the characteristics of paper" can still go letterpost to the US and Internationally. That, apparently includes, cards (postcards, sport cards, game cards, etc.) that DO NOT have attachments and are not enclosed in hard plastic holders. Soft plastic sleeves are apparently OK.
Anything else, no matter the size or weight, MUST go small packet - again to the US or Internationally. There are a lot of grey areas - for instance no attachments like spangles or cloth to postcards, but greeting cards CAN have cloth or googly eyes or whatever... There was a CP-eBay workshop on the Canada Town Square board. You might also want to read the last couple of pages of that if you're in the mood for an excercise in frustration!
None of this applies to mail staying in Canada!
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Glenda
To Golf or Not To Golf? What a stupid question!
Glenda