I am really shocked, I wouldnt dream of not doing thank you notes/photo after a wedding/special celebration. This seems to be the fashion, the B&G ask for money, provide a postbox but thats it, nothing after. Surely this is basic manners? The last wedding we went to was a large expensive affair and the B&G werent youngsters.
Same goes for birthday gifts - why do people think its ok to pop a note on FB to say thanks as a general note?