Yahoo Japan among latest adopters.
Microsoft is claiming growing momentum for its Silverlight web platform, building on existing support from content providers such as AOL and NBC Olympics on MSN.
The software giant reported an average of 1.5 million daily downloads of the Silverlight plug-in, as adoption around the world continues to accelerate.
The latest adopters include Madison Square Garden Interactive, Tencent, Abertis Telecom, Terra Networks Operations, SBSi, MNet and Yahoo Japan.
Masahiro Inoue, chief executive at Yahoo Japan, said: "Our implementation of content services enabled by Silverlight has significance for Yahoo Japan and Microsoft.
"We strive to respond promptly and appropriately to the constantly evolving internet environment and customer needs, and I have high expectations that our use of Silverlight will enable us to provide better services to our customers."
Scott Guthrie, corporate vice president of the .Net Developer Division at Microsoft, added: "Silverlight offers customers and partners the highest quality creation and delivery of media, protected content, advertising and rich internet applications."