MSNBC's brand has always been two different companies: MSNBC TV and msnbc.com. It's been extremely confusing. MSNBC TV has a hosting agreement with msnbc.com to host the webpages for the shows on the network and some of the podcasts and video clips.
In 2005, NBC bought back 32% of the interest in MSNBC TV and later bought the last 18% in the next two years. They kept the name MSNBC in the process though. Microsoft still owned 50% of msnbc.com.
Now Microsoft has sold off it's 50% in msnbc.com and as part of the agreement is changing it's name. MSNBC.com will become the website for the shows on MSNBC TV and NBCNews.com will become what msnbc.com is today in 2013.