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Just to throw my two pennies worth in....guest blogging is on the radar of Google so if you are going to start writing guest blogs that have your link in the author bio at the end, be very careful! It leaves a very obvious trial that Google can use to see if you are over-doing it on the guest blogging. Instead of guest posting, why not think of the problems that people have in stock trading and reach out to finance websites/bloggers. Think of a widget that you could create that would appeal to bloggers as this could be a source of links for months. If you get short of ideas then I'd recommend buying http://www.linkbuildingbook.com/ which has been written by Paddy Moogan. Great read!

Local directories are definitely important, this post has a great overview of where you should post: http://moz.com/blog/2013-local-search-ecosystems.  I'd recommend printing it out and going through each. On a global scale, the only other directories that provide serious value are those that are very specific to your niche, and offer some sort of objective ranking or specific information on your page.  Specific directories for your industry can be very helpful in gaining a relevant link that will look good for search and draw direct traffic.  Google has made it clear that anything that anyone can submit to has little if no value going forward.  I'd stay away from those types of directories.