We are having a few problems with our users not receiving emails on certain mail providers like hotmail. I'm working hard to solve this problem.
I've just uploaded an update:
* improving handling of mail that bounces.
* spell check for email on registration, for example if you enter firstname.lastname@example.org a fix will be suggested: email@example.com.
 and one more:
* if a user posted many images, you would get an email for every image posted. That was a bit much, now all emails from a specific time frame are combined in to one. Much better for the inbox.