The topic of your article must be about internet marketing, make money blogging & other ways to make money online. Your link can point to any website.
Your article should be unique and at least 500+ words (must pass Copyscape and Plagium).
The article can contain 1 link to an external website (can be contextual in post body or at author bio) so you have the chance to obtain a quality backlink on a well established Blog.
Guest Post on DA29 blog