Not all tech news is positive, reports the San Francisco Business Times. Twitter’s stock fell more than 15 percent today in after-hours trading .
Though Twitter is growing quickly, doubling its fourth quarter revenue, it still accounts for a tiny portion of the overall digital ad market — just 0.5 percent of global digital ad revenues in 2013, compared to 5.7 percent for Facebook and an overwhelming 32.4 percent for Google.
According to eMarketer, Twitter’s share is up from 0.3 percent in 2012. MORE.