Yes. B2B senders need to sign up for all available FBLs and suppress complainers from receiving future email. Subscriber complaints are an important indicator that helps enterprise spam filters determine if your email is legitimate or spam. Not suppressing subscribers that complain results in filtered or blocked email and may lead to fewer sales and decreased revenue. You can also use the complaint data to make improvements to your email program by understanding what content resonates best with your prospects and customers.
If you do not send to many consumer mailboxes (e.g. Yahoo!), it is recommended to sign up for all consumer FBLs as an insurance policy. Some consumer mailbox providers provide business hosting that use the same spam filters and complaint mechanisms.
Refer to List of all available complaint feedback loops (FBLs) for additional information.