DriveTheVan.com currently takes you to the VoteBuilder webpage for the Iowa Democratic Party. In case the name’s new to you, VoteBuilder is an organization that compiles and maintains the country’s largest electronic voter database. This database can be accessed by any person who’s a member of VoteBuilder (accounts are free), and used to identify all the voters in any election district in the US.
And just in case you worry about the accuracy of the information that’s included on the VoteBuilder database, then it suffices to say that all the data is collected and analyzed by the Democratic National Committee (DNC).
The uses the VoteBuilder page for Iowa has got, then, should be completely clear by now. You can access the full voters’ information for your State as described above, and use it to promote your candidate. You can create and share lists, and you can keep track of who’s going to vote for whom. Registration to the site is free, and you can also log in either with BarackObama.com, and with your NGP VAN identity.