Wow! I've been a member at ancestry.com for several months now and have spent zillions of hours entering data on family (both mine and DH's). It's amazing how much info is out there if you know a person's name and birthplace or perhaps where they lived during certain census years. Ancestry allows you to search the census data up through the 1930 census. The 1890 census was somehow pretty much lost in a fire. I have a lot of data assembled from the 1870, 1880, 1900, 1910, 1920, 1930 census years for my direct ancestors as well as for a number of their siblings. However, the loss of the 1890 census sometimes throws me for a loop.
What is exciting is that last night I found a niece who had entered her parents' names as well as her own birth name. Her father died decades ago and their family dropped out of sight. I tried contacting her but Ancestry was being stubborn and the link would not work. I'm hoping hers was not a trial membership in which case I still won't be able to contact her. I do not know her residence nor her married name, so unless I can contact her in this way, I'm not certain how else to find her.