I just tried to sign up. The "store" mentioned in the article wasn't obvious but I searched "score" and it came right up. They contracted with Experian.com to provide a free EX report with a free score. The score is a VantageScore. Funny...major typo in their Q&A: 

You will receive a credit score based on the VantageScore® model using a range of 300 – 850 (custom VantageScore) provided by Experian®. The higher the credit score, the better your credit rating.

They also state within wellsfargo.com/creditscore that WF does not use the VantageScore.

Edited to fix the URL.