I only read about this earlier but it's been going on for a while. The British Library are using Joe/Jo public to help them georeference their old digitised maps. More here. What an absolutely brilliant idea! If you don't have enough man (woman) power yourself, ask the public. There are loads of people more than happy and more than capable to help. This is not safety critical so why not? Brilliant. Well done whoever was inspired to do that.