LinkedIn developed the product, Lead Accelerator, from technology it acquired with the purchase of marketing company Bizo in 2014 for $175 million. LinkedIn’s revenue from ads on its website rose 20 percent in the fourth quarter, but the growth was the slowest in two years. LinkedIn forecast an adjusted profit of about 55 cents per share for the first quarter, way below the average analyst estimate of 74 cents, according to Thomson Reuters I/B/E/S.