These files are in TIGER/Line format. For those using ESRI software, these can be converted easily into shapefile or feature class format by using the Tiger to Coverage geoprocessing tool.
In June 2002, the U.S. Census Bureau negotiated an 8-year, 200 million+ dollar contract with the Harris Coporation as part of the MAF/TIGER Accuracy Improvement Project to improve the accuracy of the Master Address File of the TIGER/Line street files. (The Harris Corporation is "an international communications and information technology company serving government and commercial markets in more than 150 countries.")
To see a list of the county streetfiles that have been realigned in this 2005 second edition, click here. To see a cumulative list of all county streetfiles that have been realigned since the start of the MAF/TIGER Accuracy Improvement Project, click here.
I have found that the realignment greatly improves geocoding accuracy and match rate.