In the release of the new viewer posted on beta for the TNM Users Conference at:
http://viewer.nationalmap.gov/beta (Best in Firefox/Chrome)
a user can now cut and paste a WMS, REST, KML, RSS or WMTS into the search box, auto-add that to the map in one-click, zoom/pan, turn on/off any layer/basemap, save bookmark THEN re-open with that User Added Service for future reference. Previously, it would not save that User Added Service. This works for adding 1 service via search box, and we are working for multiple services added as a JSON Context Profile and capability to save that as well.
Click one of the links below to see examples of saved bookmarks in TNM Viewer with other services:
Same, but zoomed in - http://bit.ly/mvipKu
USGS Geology Gravity Anomaly OGC WMS raster service - http://bit.ly/lvSpAN
USGS Biology REST service, zoomed in to the National Park extent - http://bit.ly/lT6q2I