If you are using Responsive Web Design, use meta name="viewport" tag to tell the browser how to adjust the content. If you use Dynamic Serving, use the Vary HTTP header to signal your changes depending on the user-agent. If you are using separate URLs, signal the relationship between two URLs by tag with rel="canonical" and rel="alternate" elements.
Because the act of linking to a site does not imply ownership or endorsement, you do not need to ask permission to link to a site that is publicly accessible. For example, if you found a site's URL through a search engine, then linking to it shouldn't have legal ramifications. There have been one or two cases in the U.S. that implied that the act of linking without permission is legally actionable, but these have been overturned every time.
You should build a website to benefit your users, and any optimization should be geared toward making the user experience better. One of those users is a search engine, which helps other users discover your content. Search Engine Optimization is about helping search engines understand and present content. Your site may be smaller or larger than our example site and offer vastly different content, but the optimization topics we discuss below should apply to sites of all sizes and types. We hope our guide gives you some fresh ideas on how to improve your website, and we'd love to hear your questions, feedback, and success stories in the Google Webmaster Help Forum1.
Provide full functionality on all devices. Mobile users expect the same functionality - such as commenting and check-out - and content on mobile as well as on all other devices that your website supports. In addition to textual content, make sure that all important images and videos are embedded and accessible on mobile devices. For search engines, provide all structured data and other metadata - such as titles, descriptions, link-elements, and other meta-tags - on all versions of the pages.
Paid search results are those in the top and bottom of the results page, indicated by the small “ad” icon. These are placements that businesses pay for to show up when users search specific keywords. Google Ads can be a very effective way of utilizing ad spend for those who are new or struggling to compete against businesses that rank higher in organic search results. It’s also great for businesses targeting keywords with high revenue potential.