Many sites allow you to login with Facebook or login with Google, this is known by the tech community as OAuth2. When login with steemit becomes a reality that will change the way applications monetize and incentivize users forever. Imagine a role-playing game where users can contribute content to advance the storyline or provide helpful information for certain players. Certain games such as Bloodbourne for PS4 already allow users to post helpful tips when a user is playing with online capabilities. Allowing a login with steemit capability would allow for this type of content to get rewarded.
A steemit dedicated streaming service would also be a next level application where streamers can be incentivized to post video content. Users are already posting content from YouTube on their blogs, but one can argue that a website focused to video streaming content would garner more attention. An application such as Twitch, but with steemit capabilities would allow for all types of streamers to be rewarded. Or an artwork focused site such as deviantart with steemit capabilities would incentivize artists and also recognize them for their artwork.
A Spotify powered by steemit would encourage musical artists to produce content, as well as reward them for their hardwork. They could even charge a certain amount of STEEM to listen/download their album and get rewarded for user upvotes (just an idea, the possibilities of course are almost endless). These dedicated applications would of course be powered by a decoupled system where a user can log in with their steemit account, and all of their transactions would be recorded on the STEEM blockchain.
A login with steemit system would allow for research to get funded and curated, imagine a research focused website such as Google Scholar that allowed users to upvote research and comment and give feedback. As a member of academia I often hear that professors do not get paid enough for their efforts in creating textbooks and that most of the profits go to publishing companies. A login with steemit would fuel the development of these type of applications so that professors can get properly rewarded for their efforts.
Another implication that a login with steemit would have is in the field of security and accountability. When all transactions are stored on the blockchain there is a higher level of accountability. Applications where a user logs in with steemit and makes a transaction would be fundamentally more secure than their predecessors.
I see a future where once a user's identity is verified, they can walk into a museum and go to a painting and press a physical upvote button which based on their fingerprint would upvote that painting and record that as a transaction on the steemit blockchain. Call me crazy, but often the most fantastical ideas are the ones that make the greatest impact. :)
Thank You,
Np