Several readers have reported difficulty in reaching parts of the Internet today.  The source of the problem appears to be with AS 47868 causing AS paths to become too long.  Not much you can do about it unless you have access to your BGP router, in which case you might want to either block AS 47868 or limit the length of any AS path.  

UPDATE
Renesys has a very good explanation of what happened yesterday.  See
http://www.renesys.com/blog/2009/02/the-flap-heard-around-the-worl.shtml

Marcus H. Sachs
Director, SANS Internet Storm Center