BuddyPress.org

If only people didn’t believe that Email protocols and services were such a simple thing, the post above by deadpan10 gets closer than most to understanding some of the potential issues and that it’s NOT necessarily a WP/BP one.

Correctly set up email with correct and proper dns records might go some way to resolving issues many have, interestingly it’s pointed out that even given a correct SPF record Hotmail still appears to have issues, I have no answer to whether it’s the activation link but it’s an interesting notion.