So I went out on a limb to buy a bunch of expired domains that had some great metrics. I put some sites on some of them, others have been sitting there for a week or two now without content or anything. Well I checked on some of them today and the TF had dropped from high 20's to 10 or lower on a bunch of them. The backlinks still seem to be there so I am confused as to why this happened. Are they a complete loss or should I still build sites on them since the backlinks are there (which is what google cares about anyways not TF)?