I had added these to the release post but it will be easier for everyone to find them here.
As we get tutorials updated or added, we'll post them in this post. I'll just keep updating this one post with each tutorial so you might want to bookmark this post.
Groups - new settings for each plugin such as blog, poll, etc for member levels.
Spam and flood control settings per member level added to the following:
Sign Up Process - Two Step Authentication added.
Photo albums - added "unmapped photo" deletion option to remove photos that didn't get saved by the user, creating "orphaned" photos.
Payment Gateways - added the various manual payment methods.
Accessibility Widget - how to enable and disable the new accessibility widget.
"More" option for menus - how to enable the "More" option for menus.
More tutorials added or updated.
Added tutorial for payment gateways
Member level tutorial linked above is updated to add the new privacy settings for the profile info widget.
New tutorial added for the accessibility widget. Also, new tutorial added for the "more" option for menus.
This thread was for v5 new features added and the tutorials for those. SEO optimization would not be a software feature but a topic along the lines of site administration etc. As that is not my expertise, all I can do is point to some blogs if you would please post a new thread for your question. That would also allow other clients to chime in once they see the title of your post.