Hoping to bring about greater efficiency, Viacom's MTV Networks has formed Digital Fusion, an in-house advertising and marketing unit that will handle the company's diverse portfolio of brands online.

Jason Witt will run Digital Fusion, which will oversee more than 300 websites, covering brands that include MTV, VH1, Comedy Central, Nickelodeon and Spike TV.

Digital Fusion will work to "create entirely new digital-ad products, from creative uses of existing inventory to original interactive experiences, including video content, online games, microsites and widgets," MTV Networks said in a statement.