Traditionally, the WordPress SEO plugin is as you guessed an SEO plugin but it also has some other useful functions, here are 6 little known functions of the plugin.
WordPress SEO by Yoast is one of the most popular WordPress plugin, the plugin has currently being downloaded over 11 million times and it maintains a 4.7/5 rating on the WordPress plugin directory.
1. Sitemaps

Sitemaps inform search engines about pages on your sites that are available for crawling. A Sitemap is an XML file that lists the URLs for a website along with the metadata about each URL, it aids search engines in crawling websites in a more intelligent manner. A sitemap is submitted to most search engines through their Webmaster tools.
WordPress SEO has had a XML Sitemap functionality for a while but most people preferred using a dedicated sitemap plugin, such as Google XML Sitemaps. In 2011, the XML sitemap functionality of WordPress SEO was rebuilt and 3 years later the sitemap functionality of WordPress SEO is now used as the default sitemap plugin by most WordPress users.
Why do you need an extra plugin for generating a sitemap when WordPress SEO can handle it excellently?
To enable the sitemap function, in your admin panel, Select — SEO — XML Sitemaps —enable XML sitemap functionality.
2. Social Media Optimization

WordPress SEO not only handles search engine optimization of your WordPress site, it can also handle your social media optimization.
The Social menu in the WordPress SEO plugin can be used to optimize your content on 3 different social networks:
WordPress SEO can be used to add Facebook’s Open Graph meta data to your site’s section.
The open graph meta data helps Facebook to understand your content more intelligently.
It helps Facebook to understand the kind of content, the canonical URL of the page, the title of the page, what the page is about and which image should be shown next to the post on Facebook.
When you post your url on Facebook, the image, summary and title shown could be optimized by adding Open Graph meta data to the <head> section of your website.
You can add Open Graph data to your site by selecting SEO — Social —Facebook — Add Open Graph meta data.
WordPress SEO can also be used to add Twitter card meta data to your site’s <head>section. Twitter Cards helps to enhance your content within Tweets across the web and on mobile devices. Using a Twitter card helps your tweets stand out on Twitter.
Google+
Like Open graph meta data and Twitter cards, the WordPress SEO plugin could also be used to add Google+ meta data and of course this also helps enhance the look of your posts on Google+.
You can add Google meta data to your site by selecting SEO — Social —Google — Add Google+ specific post meta data (excluding author metadata).
3. Webmaster Tools

The WordPress SEO plugin by yoast can also be used to verify your website on various webmaster tools. You can verify your website on all of the services listed below by simply clicking on the service you want to verify on your WordPress SEO dashboard.
- Alexa Verification ID
- Bing Webmaster Tools
- Google Webmaster Tools
- Yandex Webmaster Tools
4 . Permalinks

WordPress SEO could also be used to improve the default WordPress permalink structure.
A very important function is that it can automatically remove stopwords from your permalink. Stop words are extremely common words ignored by search engines in order to save disk space or to speed up search results. he WordPress SEO plugin by Yoast helps create a cleaner URLs by automatically removing stopwords from your permalink.
To do this, go to SEO — Permalinks —Remove stop words from slugs.
5. RSS

WordPress SEO by Yoast also has an RSS feature that can be used to automatically add content to the beginning and the end of posts in your RSS feed, it is meant to act as a measure of preventing scrapers from stealing your content.
To do this, go to SEO — RSS .
6. Edit your robots.txt and .htaccess File
The WordPress SEO plugin can also be used to edit your robots.txt and .htaccess files. These files would normally require you to login to your site through FTP in order to access them but thanks to the WordPress SEO plugin you can edit these files and save changes right from your WordPress admin backend.
To do this, go to SEO — Edit Files .
By using these functions in WordPress SEO by Yoast you can reduce the number of plugins on your WordPress site. Remember the lesser the number of plugins, the better.