Sparanoid

Adds readability.com widget on your site. A must-have plugin if you’re a Readability publisher. This plugin also works fine with multisite enabled WordPress (aka. WordPress Mu).
More information please visit my <a href="http://sparanoid.com/work/readability/" rel="nofollow ugc">site</a>.

Readability Buttons (readability.com)

Adds readability.com widget on your site.

siteattention

Score higher on Google and make sure your pages get the traffic they deserve! Click the Download button to try SiteAttention FREE for 30 days – no strings attached!
Get tips on how to improve your search ranking while writing your post! SiteAttention adds a simple and intuitive sidebar with tips and an SEO score to help you improve your ranking on search engines, such as Google. All in real-time and with easy WordPress integration. Keep an eye on how each of your pages perform and see your website’s overall progress on SiteAttention Dashboard.
Get full access to all features for FREE for the first 30 days and afterwards pay just €15 per month for up to 50 published pages. 
Visit our <a href="https://siteattention.com" rel="nofollow ugc">website</a> and find out more about SiteAttention.
<h3>Configuration</h3>
In order to start using SiteAttention plugin, make sure it’s activated:
<ol>
<li>Go to “Plugins” tab, find SiteAttention and click on “Activate” button underneath, then click on “Settings” (you can also click on SiteAttention tab in the main WordPress menu) which will take you to the SiteAttention setup form.</li>
<li>In the “New customer” section write down your first name and email address, then click on Get started!</li>
<li>Congratulations! Now you can start using your SiteAttention plugin! Simply go to the post or page editor and the plugin will appear by the page you’re editing, giving you SEO tips in real-time!</li>
</ol>

SiteAttention SEO

Simple and intuitive SEO tool to help you improve your search ranking.

Readability Buttons (readability.com) vs SiteAttention SEO