Much of the spam email we all get proclaiming "deals" is a good example of email marketing at its worst. Someone somewhere buys an email list (or several) and sends an email along the lines of “Get ___________ (the product name) for only $_____! (the amount)" to everyone on the list—sometimes repeatedly. All this does is annoy everyone and give email marketing a bad name.
Spam is the biggest threat to organic search engines, whose goal is to provide quality search results for keywords or phrases entered by their users. Google's PageRank algorithm update ("BigDaddy") in February 2006—the final stage of Google's major update ("Jagger") that began in mid-summer 2005—specifically targeted spamdexing with great success. This update thus enabled Google to remove a large amount of mostly computer-generated duplicate content from its index.