when we pop certain strains we have a numbering system. usually a letter or two followed by numbers 1-xx(xx representing the # of plants we popped). m7 just happened to be my personal favorite of the bunch. I'm not good at naming things, so she stayed m7. Her lineage is unknown, but the source we got the seeds from called it "Master" hence the "m". (The plum came from the same source).
When you have local friends and family that are in the game, it gives you many more options in finding the best of best. I'm sure we are just skimming the top though...