Since the redesign I removed digg from all my websites share buttons...
Google +1 is killing those sites off... although not of the same concept, every webmaster knows not only does it help share your website but helps a little in SEO also... Google plans to increase this effect once the numbers have increased.
This said, myspace (I know awful website that long died off) was purchased cheap by News Corp many moon ago. The hits and user base made it worth several fold what it sold for - and thats coming from someone who never really liked the simplicity of the site and the pathetic Tom back-story.