Recently I have seen an uptick of Spam messages which are continuously changing their From and Subject signatures. Specifically, they are using "UTF-8?B?" signatures in the From and Subject which constantly changes so that Yahoo's present filtering is unable to catch. Without improved spam filtering, my time is being wasted deleting this garbage and I may need to move on from Yahoo mail. It would seem the paid version has something more powerful to eliminate this but this far that's not been the case.