All search engines loves relevant posts,especially relevant guest posts. In 2013 good has thrown away all those sites that have irrelevant guest posts. I mean all those guest posts that are not published on the sites that belong to their niche.
Guest posts can help with content. I think it's content that Google truly loves, more so than where it comes from.
Guest posts and guest blogging on relevant websites is very good way to take traffic on your own website. Search engine always loves that website that update their content or also love those website that get links from relevant websites.
Is this true? According to Google, Author Bios and Authorship is necessary for every website and now you're telling it would be devalued in upcoming years.
Who cares what google will do in future? The Way FB is being used for marketing nowadays. I wonder whether Google will be profitable 10 to 15 years down the line.
Absolutely! The main intention behind Guest posting should not be links and brand visibility, infact it should be to help the users of that site with the quality content, visibility and brand awareness will automatically happen.