Per Tipranks, Mark Mahaney's downgrade of Twitter has merit. His track record for calls is in the green:Source: Tipranks - To view all calls from this analystThis analyst also worked previously for Citi "amid a probe into disclosure lapses surrounding the troubled initial public offering of Facebook". He was fired. RBC hired him in 2013.I like Twitter's fundamental shift towards a "live" digital content distribution. This pushes the company away from the limited, 140 characters of content posting. This includes but does not limit its deal with the NFL.In time, Twitter's value offering for advertisers will change fundamentally in a good way.