Beginning January 2014, ICANN has added an extra step to verifying generic Top-Level Domains (gTLDs).
When you register a domain with new contact details or change the registrant (owner) email address on an existing domain—even if you've been an existing customer for years—you will receive an additional email from email@example.com with an activation link.
Please click this activation link to keep your domain active. This step must be completed within 15 days or your domain will be suspended and inaccessible until verification is complete.
Also, please add firstname.lastname@example.org to your contacts to ensure this email doesn't end up in your junk folder. This is a rule from ICANN, and they don't give exceptions. Not even if you're stranded in Antarctica (they're very serious people).
If you purchase a domain or make a change and don't receive an email, or if you just have questions about the new ICANN rules, please get in touch.