While the rest of the world refers to the late osama bin laden when referencing the term OBL but in the successful business of linkbuilding we only know it as out bound links. Now while you are asking yourself why this would matter to you or your website this is a very important factor when choosing to build or Buy Backlinks.
Outbound links are the links placed on a page that point to an external location such as another website etc. Outbound Links are a good indicator of the quality of a Backlink. The more OBL the less power or authority the links placed on a page or website. To some they refer to this power or strength as "Google Juice"