On Wednesday's edition of Investor Beat, host Alison Southwick and Motley Fool analysts Taylor Muckerman and Jason Moser take investors through the biggest stories from the market today.

In this segment, Jason and Taylor explain why they're keeping close watch on shares of Facebook (NASDAQ:FB) and Rio Tinto (NYSE:RIO). Should Facebook investors be concerned that Twitter (NYSE:TWTR) has an edge in the all-important mobile advertising space?

Alison Southwick and Taylor Muckerman have no position in any stocks mentioned. Jason Moser owns shares of Twitter. The Motley Fool recommends and owns shares of Facebook. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.