You won't be using a company for very long if they can't get your marketing to your customers. The company depends on your subscription to survive. Because of this, they have employed several methodologies:
Benchmark works with Return Path, a company that monitors the activities of the company as a whole to verify to ISPs that email marketing
that comes from Benchmark is not spam and complies with Return Path's high standards. As your email marketing comes through Benchmark's "white-listed" IP addresses, it enjoys better delivery as it is from a trusted source.
Tracking Open Rates and Complaints
Benchmark monitors its own customers to make sure that its more reputable customers are deserving of these certifications, and that individuals that are not using best practices are not sullying the reputations of its customer base as a whole. As much as your individual activities help or harm your domain's score, the sum total of all the activities of the companies who send email through an email marketing provider's servers affects its reputation. The integrity of the road is judged by all cars on the road. Good clients get the best roads on their trips towards the inboxes and bad clients are kicked off of the road.
Providing the Best Mechanisms for Unsubscribes
You might think that you'd want your ESP to provide you a system so that those who want to unsubscribe to your newsletter go through some retention activities. The exact opposite is true. You want those people off your lists as soon as possible. For one, it's the law. But more importantly, it's the ethical thing to do. Providing a quick and easy email unsubscribe process
minimizes spam complaints and improves reputation.
Working for Higher Email Marketing Standards
Spamming isn't just the enemy of the people whose inboxes are clogged with useless or offensive email, it hampers the legitimate marketing activities of reputable companies and the businesses who provide them the means to do so (like Benchmark). Coalitions like the ESPC work together to make sure its members adhere to much higher standards than state and federal law calls for. Again, better delivery rates are the end goal.
Maintaining Great Relationships with ISPs
Your ESP should work hand in hand with all the major ISPs so that your reputation is enhanced merely by association. If someone hits the Report Spam button on one of your communications, they'll go to bat for you and make your case on your behalf.