Does Yahoo’s Tumblr ‘screw up’ augur the end of another digital bubble?

The Drum's digital editor Ronan Shields points out how Yahoo's dramatic Tumblr write down is indicative of a major correction in the industry's ad tech sector.
Perhaps the most shocking element of yesterday’s Yahoo revelations was the debilitating effects of its Tumblr write down on its overall financial performance?
Despite annual increases in its search, mobile, and MAVENs revenue during the second quarter (which amounted to $1.3bn) of this year, a downgrade in the va