Pinterest takes aim at Google with auction-based pricing as it shakes up ad offering

Visual bookmarking tool Pinterest has debuted an auction-based system that allows advertisers to bid on CPM campaigns. 
Pinterest previously only allowed brand partners to purchase CPM, or cost per-thousand impressions, slots at a fixed price but the latest shakeup means they will now be able to bid on inventory on a case-by-case basis.
The bidding offering is available to all US, UK and Canadian ads using Pinterest via its Ads Manager platform, and is similar to Google'