All of our delivery servers have been 'whitelisted' by many of the larger ISP's, including AOL and Yahoo! Our servers are also integrated into the spam reporting systems for other large ISP's such as Yahoo, Hotmail and AOL. This means they're a trusted source for email origination and these arrangements ensure the best chance of your emails being delivered, it also allow us to keep any sender not following best practice guidelines off our servers.
Deep behind the scenes we monitor hundreds of the most common blacklists each and every day. If a server is ever listed (and it can happen to even the most well behaved permission-based email servers), we remove it from our delivery cluster immediately and resolve the issue on behalf of our customers.
We automatically detect different types of bounces and react accordingly. Undeliverable addresses are removed immediately, temporary fails are given additional chances before removal based on best practice.
We support confirmed opt-in for all subscriber lists, include a single click unsubscribe link in all campaigns and allow your subscribers to maintain their own subscription through preference centers.