Historically, USGS topographic maps were made using data from primary sources including direct field observations. Those maps were compiled, drawn, and edited by hand. By today's standards, those traditional methods are very expensive and time-consuming, and the USGS no longer has funding to make maps that way.
A new USGS topographic map series was launched in 2009 and branded "US Topo." Though designed to look like traditional 7.5-minute topographic maps, US Topo maps are mass-produced from secondary sources, primarily The National Map and other government GIS databases. US Topo maps are a repackaging of GIS data in traditional map form for the benefit of non-specialist map users.
One of the main differences is that the historical USGS 7.5-minute topographic map series (produced 1945-1992) included feature classes that are not yet shown on US Topo maps (though more are added each year). Examples include recreational trails, pipelines, power lines, survey markers, many types of boundaries, and many types of buildings.
US Topo maps are, however, superior to historical USGS topographic maps in some ways. Individual layers can be turned on and off to allow map customization and the inclusion of more data. US Topo maps include a high-resolution aerial photograph (orthoimage). Thanks to automated production, US Topos have a rapid national refresh cycle (3 years), as opposed to 45 years for the historical 7.5-minute map series. That leads to continuous and relatively rapid product improvement.