You can access the Search Experience Optimization settings in the dashboard at:
Dashboard > System & Settings > SEO & Statistics > Search Experience Optimization
Title Tag Format. Changes the way that the page name and site name are formatted to create the page's title tag. Most themes will honor this, but not all.
Enable Canonical URLs. This is most important for pages with pagination, but there are other circumstances where it might be useful. This setting makes sure that search engines keep all the links for each page together.
Link to Publisher's Google+ Profile. This adds a link to a publisher page on Google+. This isn't the same as an author link, those aren't used anymore.
OpenGraph Metadata. Adds OpenGraph tags to your pages. Most are self-explanatory. The OG Image Attribute Handles, however may need some explaining. This is a comma separated list of attribute handles of file/image type. The SEO addon will go through and try to find an image that can be used by OpenGraph, starting at the first attribute and going until it finds a useful image.
Twitter Card Metadata. Similar to the OpenGraph metadata, but used by Twitter. Many times this is unnecessary, as Twitter can and will use the OpenGraph tags, if they are in place.
Stopword Blacklist. This is a comma separated list of words that won't show up as keywords. They are ususally shorter, more common words such as 'and', 'him', or 'were'.
On-Page SEO Helper. Turn the On-page helper on/off.
Enable Keyword Review. Reviews the meta keyword tag and looks for correlations between those and the actual keywords in the content of the page. Useful when you are attempting to target certain keywords.
Limit Use of SEO Helper. Allow only users within certain groups to use the On-Page SEO Helper. By default, anyone who can edit the page can use the Helper.
Enable Google Analytics Filter. This allows you to set a cookie for the super user so that Google doesn't track visits by them.
HTTP Authorization. Use this if your page is behind a password protected barrier.