If your target market includes Hotmail customers, especially Millenials or the Internet generation, then take heed:
When you set up a Hotmail account, by default the junk email Filter is set to "Enhanced." This setting blocks most spam from getting to your Inbox. This is great - until a legitimate email gets blocked.
We've done a little research and testing on this issue, and found that the rumors are true - this default setting may very well be blocking your corporate newsletter, important customer communications, etc., even if it's coming from a reputable company email address. Companies that use email for sending receipts for purchases, links for downloading software, and account information may find this to be especially troublesome.
To minimize this problem, add a note in the web page where your customers first sign-up, explaining the problem, and asking them to add your domain name to the Hotmail "Safe List." Then add a reminder if possible at the exit page. This simple step may significantly and positively impact your email coverage, and improve customer satisfaction among your Hotmail-using clients.