This is a soft-verification model. We use the same techniques that Steem Cleaner team use to verify original content creators. As far as phishing operation, these are the standard verification tools used on Steemit since it's launch, that happen everyday in the comment sections across this site.  This service simply provides an option for people not wishing to put their personal details on the block chain in such a manner. 

It can also serve as a repository for the usernames of individuals who've taken the time to verify. 

The evidence required to verify will depend on the claims being made by the steemit user. Verification can take place through photos (The old photo-holding-a-sign), or through disclosure of a personal website, blog, or shout outs on social media accounts. This is nothing new. The only new addition are badges, that can be a quick and fun indicator to tell if a user has been verified. 

It also allows users to be proactive about verification before they can be accused of fraud, which can be very unsettling to new users.