BlackBerry ( BBRY) is another popular search. A new popular app becomes available for users of the BlackBerry 10 device on Thursday. BlackBerry 10 users can officially download the WhatsApp Messenger application, which allows users to exchange messages without having to pay SMS fees. The app uses the same mobile Web connectivity used for checking email and browsing the Web. This comes in handy particularly when users are communicating with one another internationally. According to BlackBerry, the app demonstrates the BlackBerry 10's multitasking abilities -- using "real-time push notifications" to alert users of messages even when the device's screen is locked. There's also tight integration with BlackBerry Contacts so users can start messaging people right off the bat. The app is available for download via BlackBerry World. The chatter on Main Street (a.k.a. Google, Yahoo! and other search sites) is always of interest to investors on Wall Street. Thus, each day, TheStreet compiles the stories that are trending on the Web, and highlights the news that could make stocks move.-- Written by Brittany Umar.