Email Blacklist
If some of those other sites are sending out mass spam emails, your site will be associated with that spamming. All it takes is a bunch of recipients to tag an email as spam, and, before you know it, your IP address will be added to an email blacklist. To say the least, this isn't good news for your company. You can try to get your email removed, but this is timely and costly. Here's a better option.
Outsourcing Your Email
If you outsource your email services to a third-party email provider that focuses entirely on email, the chances of your email being blacklisted are slimmer. Most of these third-party providers have strict terms in place for the prevention of email spamming. So, the chances that your email will wind up on a blacklist is slim to none.
If you send out email lists, it's still advisable to use a third-party provider. If you try to send out a mass email using your personal email, you'll be blacklisted for sure. If you use an in-house mailing system, you can still reach those spam limits if you go over 250 recipients (and most companies do).
Safe Ways to Send Out Lists
The only really safe way to send out a mass email is to send those notices to people that have opted into your email newsletters. If you're only sending out notices to people that want to get them, you will not be blacklisted. Just don't send out mass emails to everyone on your contact list – this will lead to the blacklist quickly.
Email Blacklist: Getting Your Name Off of A List
As mentioned earlier, it is possible to have your email removed from a blacklist. To do so, you have to contact a company (like Google's Gmail), and explain to them why you don't deserve to be on a blacklist. This also has to come from the CEO of a company. While this sounds simple, Rackspace has estimated that it takes approximately 4 hours to successfully remove an email from one blacklist. If you've been added to a number of those lists, that time can be extensive.
It's a far better option to simply go with a third-party email provider. This way, you don't have to worry about being blacklisted, and you can send out all the emails you wish. If you want to go the mass email route (but, really, this only works if people actually want to read your emails!), let a third-party mass emailing company handle what you want to send out.
Emailing on the part of a company can be tricky. All it takes is a bad IP address or a few people marking your emails as “spam” to be put on that blacklist.
Got questions? Need help? Just ask!