Nielsen this week pretty much legitimized the work that advertising sell side platform Clypd and its associated broadcasters have done over the past few years, building a new Audience Forecasting tool in time for this year’s Upfront negotiations. The aim seems to be to bring what Nielsen describes as “audience based buying” but on the TV, rather than online. It says that this brings both consistency and transparency to buying advertising by audience on the TV. It does this by simply using Nielsen data to predict the size of each audience accurately in advance. Clypd has been around since 2012 and has recruited Disney’s ABC, A+E, AMC Networks, Discovery Communications, Fox, GSN, Scripps, The Weather Channel, 20th Television and CIMM…