When you're trying to grow your organization, getting a ready-made list of leads that you can email can be very tempting.

Maybe you found a directory where people are listed, maybe you purchased a list from a broker, maybe a strategic partner offered to let you email to their people... all of these probably feel like an ideal way to get in front of your audience. 

However, if you do not have a business relationship with these people, you will very likely get lots of bounces, unsubscribes, and complaints. This can do permanent harm to your deliverability and you can actually be black-listed by email providers like Google, Microsoft, Yahoo, Comcast, etc. 

If you absolutely must use a list of people who don't have a relationship yet with you (which again, is NOT recommended):

1. Proceed VERY slowly. Do not blast the entire list at once. You WILL get yourself labeled as a spammer because you actually *are* a spammer.  Emailing people who haven't given you permission and don't know you is the literal definition of spamming, so don't be surprised if the email gods strike you down.

2. Run your list through a validating system to check for bad emails.  This is not foolproof, but there are services that can check through a list to get rid of obvious bad addresses.

In the case of using a strategic partner's list, I recommend having the partner do the email introduction using their email list... and offer a link over to your website where they can connect with you. This poses no risk to your email reputation and the partner is giving you a "warm introduction" to their people which goes much farther than a cold email from you as an unknown entity.