This plugin for josm works extremely well for cadastral type wms information.
Obviously the wms needs to be licenced CC-BY-SA
There are a number of these available.
The German one that comes with the plugin provides a good example for tracing buildings.
The only issue I've found is that it appears to have problems with some wms that use https: for the protocol.
Australian CC-BY-SA wms
Tasmanian cadastral
Licence info: metadata
Url to use in Tracer2
wms:http://services.thelist.tas.gov.au/geoserver/PUBLIC/wms?SERVICE=WMS&FORMAT=image/jpeg&TRANSPARENT=TRUE&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&LAYERS=Cadastral_Parcels&STYLES=&SRS={proj}&WIDTH={width}&HEIGHT={height}&BBOX={bbox}
Queensland cadastral
Licence info: metadata
Url to use in Tracer2
wms:http://geospatial.information.qld.gov.au/ArcGIS/services/QLD/LandParcelPropertyFramework/MapServer/WMSServer?FORMAT=image/png&TRANSPARENT=FALSE&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&LAYERS=Cadastral Parcels - All&STYLES=&SRS={proj}&WIDTH={width}&HEIGHT={height}&BBOX={bbox}
Both of the above the have a https:// server as well but do not work correctly with the tracer2server.
Victorian cadastral
Licence info: metadata
Url to use in Tracer2
wms:http://services.land.vic.gov.au:80/geoserver_pWMS/wms?SERVICE=WMS&FORMAT=image/png&TRANSPARENT=FALSE&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&LAYERS=sii:VMPROP.PROPERTY_VIEW&STYLES=&SRS={proj}&WIDTH={width}&HEIGHT={height}&BBOX={bbox}
Further comments on usage.
Details for installing and using tracer2 are here
As the plugin first looks to find the top line of the area it's best to click near the top of the area you want to trace. That way it does not have to search through a lot of blank imagery to find the starting line.
If your tracing large areas >1km square then set the tilesize to 0.002 or larger and the Resolution to 1024 or less.