I have created this account to use for imports, my main account is (predictably) keithonearth.

So far I’ve only imported data from the City of Vancouver Open Data Catalogue Building footprints 2009. For this import I selected a small section (about a square km), checked if any of the buildings had been already traced by comparing with the standard rendering. I gave OSM data priority, including the unusual case when the CoV data more accurately represented the satellite imagery, and did not import any buildings that were already in the OSM data. I retagged the footprints as building=yes or building:part=yes, and the HGT_AGL as height=*. I then reviewed the CoV building footprints a second time in comparison with the Esri World Imagery (which seems to be the most up to date, and high quality), any buildings that were not in the imagery were not imported. I then validated the data with JOSM, and uploaded it from this account. From my regular account I downloaded with the rest of the OSM data, and validated again. The whole process is very labour intensive, and manual, but results in pretty high quality data, and is faster than manually tracing all the buildings.