Social network Twitter kicks off another interesting week for technology stocks. Let's look at the tech stocks to watch Tuesday: Twitter. The company will report second quarter earnings when the markets close Tuesday. Twitter is expected to report a loss of a penny per share off revenue of $283 million, according to estimates compiled by Yahoo. But the key metric investors will follow are Twitter's monthly active users. During its first quarter, Twitter said it had 255 million monthly active users. Yelp. The recommendations service is now allowing users to add videos to their reviews. In a blog post detailing the new feature, Yelp says the inclusion of videos will give users the chance to "show off aspects like ambiance, lighting, noise level, and other features of local businesses not easily captured by photographs." Yelp will report quarterly earnings Wednesday. Microsoft. The company's Windows Phone mobile operating system welcomes a big addition to its app store: Fitbit. The fitness band and app are now available for Windows 8.1. It will work with the Flex, One and Zip activity trackers. Apple. The company has bumped up processor speeds on its line of Macbook Pros with Retina displays, reports The Next Web. Entry level, 13-inch models will include a 2.6GHz dual-core Intel Core i5 chip and 8GB of memory. T-Mobile. The wireless carrier reports second quarter earnings Thursday. On Monday, the company unveiled its latest promotion: a new family pricing plan where a family of four can share 10 GB of data for $100 a month. Source: http://www.usatoday.com/