From Affiliate Wiki
affiliates are fickle and busy folk, you really must adopt the correct communication strategy with them.
Just like any sales force they need up to the minute information about your products and services BUT at a level that is suited to them as an individual or company.
i.e someone who works with you on a Paid Search basis in a turbulent market will want to know when mobile phones are in or out of stock, new tariffs that arrive, or new phones. An affiliate operating a loyalty website may find too much information overwhelming when they have hundreds of partnerships to manage.