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Structured data - Schema is Good for SEO ! So ... Check if structured data aka schema, microdata is being used on any given web page with webmaster tools <a>www.google.com/webmasters/tools/richsnippets</a> If you are trying to improve the page you can also use the Structured Data Markup Helper - html conversion tool to have Google auto-add schema to the page after you choose the relevant category: <a>https://www.google.com/webmasters/markup-helper/</a> This is of course just one more method to use in addition to others mentioned.

Generally agree with everyone (well, everyone so far ) - there's no need to remove authorship in general. Google isn't penalizing sites with authorship - they're just showing authorship thumbnails less often, as they found they were overdoing it (at least in the eyes of users). The only exception I'd give is to be careful about applying authorship tags to every page on a site - home page, search results, product pages, etc. Some CMSs go crazy, unfortunately. This is technically against Google authorship guidelines. Again, most likely, they'll just ignore your authorship mark-up (it's not a penalty situation), but if you want that mark-up to appear in SERPs, then use it appropriately.

I prefer to keep it simple. List a few references and related examples of what you can do and ask if they would like to chat with you in more detail so you can provide an accurate quote and address any specific questions they may have.

You have 5 identical sites but you want to solve the duplicate problem? Then change each site and their content?

it is not just about links from social media that OSE fails to show, there is whole a lot of links from elsewhere, and it has got nothing to do with a "no follow" link from social media as you can get to select which back links you want to see in OSE

There is no hard and fast rule on maximum number of outbound links a page can/should have or at what at number they begin to lower the value of the page they're on. If all the links on a page are well curated and relevant to the topic of the page or of the site, then having your link on that page too is not going to hurt you. However, as with most things in SEO, there is a "scale" factor,and if all your back links are coming from pages with hundreds or thousands of links, you''re likely to run into problems. As for the value of such a link--think of the total value that a link from a page can provide as water in a bucket and the more pagerank or authority a page has, the bigger the bucket and the more water is able to fit into it. Now divide that water up by the number of out bound links--the fewer number of links, the more value each passes, the greater the number of links, the less value each one can pass on, until the value becomes so diluted that each one is worth next to nothing.

Do the blog links help to answer or provide further information on the question? If so I'd say it isn't a problem as long as it isn't done to excess. 100s of links from one website sounds like a lot so you should be careful depending on what quality and quantity of external links you have elsewhere. Yahoo Answers links are nofollow so you won't be getting much (if any) link juice from them.

It's good to keep in mind that the Google keyword tool isn't 100% accurate, and it's often VERY wrong when it comes to smaller keywords. Just because Google suggests a small number of monthly searches per month doesn't mean no one's searching for it or for very similar related terms. Also keep in mind that organic search isn't the full story. There are personal bloggers who made money without even trying to target terms. They simply built an audience through great quality writing and content. XKCD, for example, gets millions of visits per month. I guarantee most of the traffic to XKCD is direct, referral, or using Google to find something specific they've already seen. So the fact that there's 0 or )-) search volume doesn't necessarily mean it's not worth writing. Finally, don't trust anything Alexa tells you. I've seen their guesses estimate 10-50x too low or too high. I'd doubt the site is making "good money". I think they're just trying to grow traffic at this stage.

It could even be as simple as greater competition among sites that are relevant to the same search queries your pages are relevant to.  Be sure to examine the top sites showing in the results for your target search queries and see what's working for them.

I am not sure but if you are asking how much DA and PA is required in an incoming link that will be considered as safe. If this is your question then there is no such restriction or recommendation in this area. If the website from where you are getting a link have a clean link profile and no SPAM links pointing to that site then in that case no matter what the DA or PA of the website is the link from that website will be secure. Similarly, If a website that is pointing back to your website have a decent DA and PA but link profile of that website is spammy, in that case the link will be considered as a risky link. If the website is quality and link profile is clean then having a better DA and PA from where the link is coming will be considered as a lil more powerful as compare to a website that contain a lesser DA and PA. Hope this helps!

Domain Authority is a metric that Moz uses, but is not a metric that any search engines use for ranking.

I think 2nd edition is the latest one.