To be simple what these people do is they will collect contacts through the online facilities. once after gathering the contacts, they will send emails all together. since more emails were sent within fraction of seconds, they goes into spam. The other problem in this is, the people who are not in need of this product will also be receiving these mails. The total effort goes in vein.
To make the email marketing effective there are certain factors to be noted, like the mails should not be sent in bulk, they must be sent only to the people who are in need of this product. and the most important thing is the subject used in this email. the words like free, offer should be strictly avoided. The spam words will take the mail automatically to spam, hence they should also be avoided.