Sometimes you find historic and genealogical information in the strangest places. For instance, on Flickr, the photo-sharing site.
The Old Boston Collection, a series of late 19th century photographs of historic Boston sites, was rediscovered by the Boston Public Library (BPL) in 2007. Although the origin and early history of the collection remains a bit of a mystery, BPL employees believe that the prints represent the work of photographers affiliated with the Boston Camera Club. Most of the photos were made between 1850 and 1898. Indeed, one photograph clearly shows an 1898 calendar hanging on the wall.
In the case of older buildings that had been destroyed or significantly changed by 1888, photos were taken of old engravings. One example would be the birthplace of Benjamin Franklin on Milk Street. The nineteenth-century photographers took a photograph of an old wood engraving of the building.
Many of the notable buildings were the homes of the wealthier citizens of the time in Boston, Dorchester, Mattapan, and nearby communities. Perhaps your ancestors lived in one of these homes. Other photographs include the State House (which seems little changed today) and the cemeteries of Boston.
You can see this collection of old photographs at http://www.flickr.com/photos/boston_public_library/sets/72157607471461913/.