By Dave ClementsAccording to some estimates, upwards of 100 million spam e-mail messages are sent per day. As that number continues to grow, so does the effectiveness of spam filters in blocking unwanted mail. Users are also becoming increasingly skilled at deleting spam messages from their inbox before they can even be read.When it comes to marketing multifamily projects on the Internet, e-mail is a valuable tool—and yet, the sheer quantity of unwanted spam makes it difficult for truly valuable e-mail marketing messages to reach their targets and make an impact. This means sales and marketing teams need to be…