5:00 PM -- Today on Contentinople:

• Video measurement firm Visible Measures raised another $10 million in a Series C round of financing led by Northgate Capital. Altogether it's raised more than $29 million.
  
  
• Contentinople's Peter Baldwin tells the story of radio veteran Sam Kopper, who's working on the revival of radio through Boston station WBCN’s new HD radio project, "Freeform 104."
  
  
• Content delivery network Limelight Networks has a deal with PBS to help unify the public broadcaster's content distribution for its more than 350 member stations.
  
  

And in today's News Bits, President Obama Tweets about his first online townhall meeting.

— The Staff, Contentinople