Mailbox Provider Weighting is a feature that adjusts your seeded campaigns’ inbox placement results based on the composition of your subscriber list. With this feature, you can input custom weights for certain mailbox providers, such as Gmail and Yahoo!, that you know are important to your program. Once you have Mailbox Provider Weighting configured and applied, your deliverability data can be closer aligned with your actual subscriber list.
Without using the Mailbox Provider Weighting feature, your deliverability data would reflect the percentages for each domain in Return Path Platform or Inbox Monitor, which may not correspond to the real percentage the domains represent on your list.
For example, if you have a high spam rate at an international mailbox provider like Free, but only a small percentage of your list contains free.fr email addresses, the spam problem at Free may cause your deliverability to look worse than it is in reality. Conversely, if you have a high spam rate at Gmail and 60% of your subscribers have @gmail.com addresses, your overall deliverability may look a lot better than reality for that campaign when averaged, if you are doing well at other mailbox providers.