Just an idle question - is there any way of retrieving (i.e. To re-read, not to delete) a postcard that has been sent? I can't see anything obvious, but may be overlooking something.
Postcards
Do you mean a private message? If so: Yes, you can, assuming the PM was sent during the last three months. Go to your message center (top right), and click on "Sent Messages" right above the green "Send a Message" button.
If you don't mean a private message, then can you clarify what you mean by "postcard"? What page (with which URL) do you go to to send those?
As far as I know, there is only ONE definition of what a postcard is still today.
https://www.google.ca/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=postcard
That's my question too. What exactly do you mean by "postcard?"
An electronic communication or an old fashioned postcard letter going snail mail?
I mean when you select a photo from the gallery and click on the 'send as postcard' link, and turn it into an e-postcard. I get an email when the postcard has been collected from Travellerspoint by the recipient, but the email itself doesn't include a link to the actual postcard.
Post 6 was removed by a moderator
Ah! I had all but forgotten that functionality existed.
Hmm... *tests a bit* No, sorry, there indeed doesn't seem to be any easy way for you as a sender to read what you sent. I guess it behaves quite a bit like a real postcard that way. 
Your best bet would be to ask the recipient to tell you / give you the link they received. That should remain valid for the full 4 weeks after having been sent, so you could also use it to read the postcard yourself.
Begs the question, why do you want to re-read it? Methinks there is a story in there somewhere. 