Recently I received an email with a ".pdf" at first I just figured it's either some type of virus, spam or some other type of malware. I deleted it at first. Then I read this article and double checked the email again and sure enough it fell under "Pump and Dump Stock Scammers" . What first drew my attention to this type of email was the type of attachment was the file type used which was the first time I noticed them using a .pdf file type(associated with Adobe Reader). I've received these "Pump and Dump" type before but not like this. A quick definition of "Pump and Dump" is an email or message urging you to buy a certain type of stock in hopes to "pump" up the price of a particular stock. They generally are harmless and probably fall under the annoyance type of spam. More on this subject can be found in an article by Mary Landesman on About.com website.