IssueMap is a project created by the Federal Communications Commission (FCC) and FortiusOne to make it easier for citizens to create their own maps and share them widely across social networks (Twitter, Facebook, email). It can make a thematic map from a spreadsheet or table of data that references a geographic boundary and a set of values you would like to map to those boundaries. IssueMap does not currently geocode street addresses and only joins data to geographic boundaries.
Here is a short video explaining IssueMap.
Sachiye Day, VERTICES intern