Problem
When submitting the customers registration form, no account gets created. Instead, we get send back to on an empty registration form, customer registration not possible. No errors shown or logged.
Cause & Solution
Our registration’s template file (built from rwd) was missing the formkey-block needed for CSRF protection, so it was quite simple to fix:
Open app/design/frontend/drp/default/template/persistent/customer/form/register.phtml and add the following line somewhere between the form tags (I added it right after the opening tag):
<?php echo $this->getBlockHtml('formkey'); ?>
Sources
I got to the cause of this problem through this stackexchange question, thanks.
(At the time of writing we were working on a Magento CE 1.9.2.2 install on Ubuntu 12.04 / PHP 5.3.10)