NBCU has opened an online archive of clips and content, at NBCUniversalArchives.com. The site contains content from a number of studios and channels, some going back more than 70 years. The site, while providing free previews, is set up to serve primarily as a licensing mechanism. This follows on the Discovery Networks earlier announcement (see this post) that they were making much of their stock footage available through an e-commerce site.
Both are good examples of two of the major business strategies for media producers - find additional ways to monetize your content, and focus on licensing as a mechanism for future revenue streams.
Source: "NBCU puts Archives Content Online" Media Daily News