Social Explorer is the choice if you are looking for historical census data. In Social Explorer you will have access to the U.S. Decennial Census back to 1790 as well as the data from the American Community Survey from 2005 to 2013. This is also the source for the Religious Congregations and Membership Study (RCMS) for 1980, 1990 and 2000, the Infogroup Religion 2009 and 2010 and the 2002 Carbon Dioxide Emissions data.
SimplyAnalytics is the place to go for marketing and business data. You can get point data for over 4.5 million US Businesses and Points-of-Interest including their contact and general information. You can also access market and media research industry data from Mediamark Research, Inc. Easy Analytic Software Inc. (EASI) has created a Life Stages data set that is also available through Simply Map.
The Yale SimplyAnalytics subscription provides access to the Census data from 2000 and 2010, each in the 2000 and 2010 boundaries geographies.
PolicyMap has the largest selection of variables about communities of the three options. In addition to business data, there are are also variables that cover many aspects of housing, lending, income, health and quality of life. These variables have been collected by The Reinvestment Fund, "a nonprofit community development financial institution that works across the Mid-Atlantic". Browse their wide selection of variables to get a sense of the time periods and locations covered, as some of the coverage can be for a relatively small area.