The Pottermore Insider Blog has been updated with some more frequently asked questions about the Magical Quill Challenge.  They also reveal that the clue for August 3rd will be released between 2pm and 6pm BST (or 9am – 1pm EST). Some of the new FAQs are as follows:

I have seen people offering to register early access accounts for others. Is it safe to give my personal details to someone who is offering this service?
Absolutely not. You should never share personal details online unless you are certain how they will be used and protected. Also, please note that the transfer of Pottermore accounts is expressly prohibited in The Magical Quill promotion Terms & Conditions.

Once I’ve clicked on the link in my registration validation email, will I be able to access Pottermore?
We will not be enabling early access to the site straight away. Once The Magical Quill challenge is over we will begin to send Beta registrants Welcome emails as and when they will be able to have full access to the site. We won’t be able to let everyone into the Beta site at the same time, so you may have to wait a number of weeks for your Welcome email to arrive. However, if you have been successful in registering during The Magical Quill challenge, we can confirm you will gain access ahead of the site opening to all in October, so please be patient!

Is there any update on the Yahoo! Mail issue?
This has now been resolved and everyone who registered with a Yahoo! Mail account on Sunday or Monday should now have received their validation email.