Should the Facebook's, Google , Amazon's of this world operate a BGP looking glass ?

Hi All Should major social networking sites like Facebook,Google and Amazon operate an IP looking glass ? i think they should , here is a short justification write-up i did , using a real life troubleshooting scenario. http://www.slideshare.net/peterehiwe/why-major-content-providers-need-an-ip-... -- Warm Regards Peter