I've built floating branches of matches that do have some tree and/or profile information to get me started, in some cases my 'deep and wide tree' approach leads to me linking no tree/no profile matches along the way.
Other times the no tree/no profile match has shared matches that can help narrow down the dozens of births in the name to a small number of more likely candidates. In that case I'll make a list of births and try to rank them from most to least likely, I build the trees of two or three at a time and delete them if they don't intersect my existing tree and move on down the list.
In one case I had a an active but unresponsive match, no tree, profile, age or location. There were something like 60 births in the name on freebmd from 1925 onwards, it took me 5 trees to find the right one (his grandmother appears to be illegitimate), every fortnight or so he pops up in my tree viewers, he still reads and ignores messages but a month or so ago suddenly had a small private non searchable tree, I've just checked his profile and his private tree is now over 450 names. Maybe I've woken him up somehow.