i get 2 or 3 every day and have been for quite awhile. i opened one once just out of curiosity and it had a trojan attached. keep your anti virus up to date. wish i was smart enough to send these idiots something back that would trash their pc's. like 440 volts of 3 phase. once when i lived in phoenix i went on vacation for a month, and when i returned, i found my next door neighbors, who were bums, and apparently had their power shut off, had run an extension cord over the fence, and were stealing my electric through an outside receptacle which i had installed myself. so i promptly went to the power panel, and rewired it direct up to 220. the result was a blown up tv and some high end audio gear, which turned out to be stolen. they even had the audacity to call the law! i had a good laugh, and so did the cops as they were cuffin and stuffin 'em. they also had several stolen chainsaws in there, as apparently they thought they were arborists, too.
