I found a travel wallet at my local home station on my way home last night containing an annual rail card, oyster card and two staff passes. Thankfully the person who had lost it had a rather unusual name so i looked it up on Facebook to see if there'd be a match. There were two so I messaged them both... one replied this morning saying it's hers and we're meeting up at Waterloo after work so I can return it to her.
She described the contents of what was in the wallet so I know it's OK.
But good old Facebook - pain at times, but really great other times