Welcome to this morning's edition of "First To Know," a series in which we keep you in the know on what's happening in the digital world.

Today, we're looking at three particularly interesting stories. It might not be long before Twitter goes public: The company is expected to file its public IPO papers as soon as this week, according to a report in The Wall Street Journal. In a new advertisement showing off the latest iteration of its Windows 8.1, Microsoft highlights the return of the start button. And the tallies are in: Apple claimed the No. 1 spot for most valuable brand on Interbrand's 2013 global brand rankings.

Check out the video above for more on these stories.

Image: Microsoft/YouTube