I have been testing a number of different social book marking tools which offer plug-ins for WordPress blogs.  This has been an interesting experience.  Not all plug-ins are created equal. 

Quite a few offer a degree of granularity that I do not require at this time, others simply do not offer the ease of use that I need. 

addthis.com seems to be different.  Simply download and install the plug-in and it places the bar that you can see just below this post in place.  When you click on it, you are taken to a page where you can choose which services you wish to submit the blog to.  It is really quite simple.  I hope that it works equally as well.