[steemit] Add open graph for social media optimization

Components

Adding a new post at https://steemit.com/submit.html

Proposal

Issue:

It is currently not possible to optimize steemit posts for social media, specifically facebook, using open graph.

Solution:

Add optional input fields to the post submission form that will be used for the open graph meta tags on the post pages:

1. “Facebook Title” with this hint “If you don't want to use the post title for sharing the post on Facebook but instead want another title there, write it here.”
2. “Facebook Description” with this hint “If you don't want to use the meta description for sharing the post on Facebook but want another description there, write it here”
3. “Facebook Image” with this hint “If you want to override the image used on Facebook for this post, add the URL here. The recommended image size for Facebook is 1200 by 630 pixels.”

These would be coded according to the open graph protocol at http://ogp.me/

Mockups / Examples

Benefits

As steemit grows in popularity, more influencers will start taking notice and signing up. Many of them have a large following on Facebook and other social media platforms. As they switch to steemit as their blogging platform of choice, they will expect to be able to format their social media posts the way they want, and most other blogging platforms allow. Sharing content on Facebook that is well formatted for that specific media also increases the chances for it go viral even if the person sharing it doesn’t have a large following. This will improve the image of steemit as a more mature blogging platform that is integrated with social media as well.