http://example.com/link/look-at-this-cool-site/

http://example.com/quote/example-quote-post

http://example.com/just-another-post

<?php
/**
 * Plugin Name: Post Format Permalink
 * Plugin URI: https://wordpress.stackexchange.com/q/70627/19726
 * Description: Include the post format slug in your permalinks. Simply use the <code>%post_format%</code> tag as part of your custom permalink.
 * Version: 1.2
 * Author: shea
 * Author URI: https://wordpress.stackexchange.com/users/19726
 */

add_filter( 'post_link', 'post_format_permalink', 10, 2 );
add_filter( 'post_type_link', 'post_format_permalink', 10, 2 );

function post_format_permalink( $permalink, $post_id ) {

    // if we're not using the %post_format% tag in our permalinks, bail early
    if ( strpos($permalink, '%post_format%') === FALSE ) return $permalink;

    // get the post object
    $post = get_post( $post_id );
    if ( ! $post ) return $permalink;

    // get post format slug
    $format = get_post_format( $post->ID );

    // set the slug for standard posts
    if ( empty( $format ) )
        $format = apply_filters( 'post_format_standard_slug', 'standard' );

    // apply the post format slug to the permalink
    return str_replace( '%post_format%', $format, $permalink );
}

<?php
/**
 * Plugin Name: Post Format Permalink
 * Description: Allow to use Post Format as Permalink; inlcude %postformat% in custom permalink
 */

class Fb_Add_Post_Format_Permalink {

    function __construct() {

        add_filter( 'pre_post_link', array( $this, 'generate_permalink' ), 10, 2 );
        add_filter( 'post_rewrite_rules', array( $this, 'rewrite_rules' ) );
        add_filter( 'generate_rewrite_rules', array( $this, 'generate_rewrite_rules' ) );
    }

    function generate_permalink( $permalink, $post ) {
        global $standard_slug;

        if ( FALSE === strpos( $permalink, '%postformat%' ) )
            return $permalink;

        if ( ! is_object( $post ) )
            $post = get_post( $post_id );

        $postformat = get_post_format( $post->ID );
        if ( empty( $postformat ) )
            $postformat = ! empty($standard_slug) ? $standard_slug : 'standard';

        return str_replace( '%postformat%', $postformat, $permalink );
    }

    function generate_rewrite_rules( $wp_rewrite ) {
        global $clean_post_rewrites;

        $wp_rewrite->rules = $wp_rewrite->rules + $clean_post_rewrites;
    }

    function rewrite_rules( $post_rewrite ) {
        global $clean_post_rewrites, $wp_rewrite, $standard_slug;

        $wp_rewrite->use_verbose_page_rules = TRUE;

        $post_format_slugs = implode( '|', get_post_format_slugs() );
        if ( ! empty($standard_slug) )
            $post_format_slugs = preg_replace( '|standard|', $standard_slug, $post_format_slugs, 1 );

        while ( list($k, $v) = each( $post_rewrite ) ) {
            $new_k = preg_replace( '|%postformat%|', '(' . $post_format_slugs . ')', $k, 1 );
            $clean_post_rewrites[$new_k] = $v;
        }

        return $post_rewrite;
    }

}
$post_format = new Fb_Add_Post_Format_Permalink();