I send out a lot of cards and notes - both handwritten and electronic. I have been laughing out loud quite a bit since an edgier friend of mine told me about "someecards."
Warning - these cards are not your average wholesome, Hallmark-style greeting cards and some have a bit o' colorful language. They're more of a fit for people like me who enjoy The Onion or The Office (British, American, or the must-see Japanese version).
If you're looking for non-traditional, humorous ecards, then someecards should be your next click.