Yahoo has started to inform users about the availability of usernames which they have requested via Yahoo wishlist. This was declared by Yahoo! on their official tumblr blog. This step probably would be last one for users if the usernames which they requested via wishlist are available.
On 12th June 2013, Yahoo! decided to blessed their users by giving a chance to renew their email accounts with new Yahoo usernames (link). On 15th of July, everyone got a chance to request up to 5 desired usernames via Yahoo wishlist in order to get a short, memorable and simple email ids, absolutely free (link). On 16th August, Yahoo sent emails to users about removal of all old inactive email ids in order to inform if any inactive email id's were deleted from user contact list (link).
In case if the username which you had requested is not available then, Yahoo! will allow you request more via wishlist for free.
The top three Yahoo username requested by males via wishlist are David, Michael and Alex. Females three most requested names are Maria, Jennifer and Jessica.
You can also join waiting list to get short and unique email id if you weren't join it in July but, this time you should have to pay $2 USD.