The rising price of Twitter's promoted trends ad service proves there's money in them there tweets. Twitter, AllThingsD reports, has been steadily increasing the price it charges for a company to sponsor a "promoted trend" in users' Twitter webpages and inside mobile apps on top of the real chatter-driven trends sourced in tweet streams. The service cost went up earlier in 2013, and it now costs $200,000 per day (and per territory, though where territories start and stop appears to be unclear)--up from $150,000 in 2012 and $80,000 at launch in 2010. Those are like NYC subway fare spikes! ... Read More