A Coursera Specialization is a series of courses that helps you master a skill. To begin, enroll in the Specialization directly, or review its courses and choose the one you'd like to start with. When you subscribe to a course that is part of a Specialization, you’re automatically subscribed to the full Specialization. It’s okay to complete just one course — you can pause your learning or end your subscription at any time. Visit your learner dashboard to track your course enrollments and your progress.
When would this be useful? If your site has a blog with public commenting turned on, links within those comments could pass your reputation to pages that you may not be comfortable vouching for. Blog comment areas on pages are highly susceptible to comment spam. Nofollowing these user-added links ensures that you're not giving your page's hard-earned reputation to a spammy site.
Google asks quality raters to investigate your reputation by searching “giving the example [“ibm.com” reviews –site:ibm.com]: A search on Google for reviews of “ibm.com” which excludes pages on ibm.com.” – So I would do that search yourself and judge for yourself what your reputation is. Very low ratings on independent websites could play a factor in where you rank in the future – ” with Google stating clearly “very low ratings on the BBB site to be evidence for a negative reputation“. Other sites mentioned to review your business include YELP and Amazon. Often – using rich snippets containing schema.org information – you can get Google to display user ratings in the actual SERPs. I noted you can get ‘stars in SERPs’ within two days after I added the code (March 2014).
Submit website to directories (limited use). Professional search marketers don’t sub­mit the URL to the major search engines, but it’s possible to do so. A better and faster way is to get links back to your site naturally. Links get your site indexed by the search engines. However, you should submit your URL to directories such as Yahoo! (paid), Business.com (paid) and DMOZ (free). Some may choose to include AdSense (google.com/adsense) scripts on a new site to get their Google Media bot to visit. It will likely get your pages indexed quickly.