Useful for any railcard holder (like 16-25 young persons railcard). You can get it linked to you oyster for lower daily caps. But you have to have some difficult conversations with ticket office workers. Instructions here for the ticket office man http://www.oyster-rail.org.uk/railcard-discounts/

"Fancy cheaper tube fares? They're yours if you have a Gold Card. That's the special bonus bit of cardboard given to everyone in London and the southeast who buys an annual travelcard for their train journeys. A Gold Card saves one-third off all off-peak fares on National Rail (mine saves me a packet every time I head out of town to the seaside or somewhere). And now, as of this month, it saves one-third off all off-peak fares on London Underground too. Who knew?"

Also, you can look up your surname on http://worldnames.publicprofiler.org/ to get a worldview of your family's dominance.