For those people that are researching ancient records in the U.K., the Domesday book is an invaluable but at times indecipherable and non-indexed source. Help is on the way. Anna Powell-Smith and others have taken the scanned images done by Professor J. J. N. Palmer and have indexed the pags by places, towns or postal codes. You can see locations on a map and view populatios and tax assessements (in "geld" units) at the time. The households can include: head of manor, ploughland size, name of Lord and Tenant-in-chief, in 1066-1086. Fun to explore. The website home page is: http://domesdaymap.co.uk/.
A description of thw ork by Powell-Smith can be found at: http://openglam.org/2012/02/02/opening-up-domesday-book/.