Microsoft essentially ended its relationship with Perion. Shares of Perion Network (PERI -28.29%) were tanking today after the company's relationship with Microsoft took another step back, crushing a key source of revenue for the ad tech company. As a result, Perion slashed its revenue guidance again, following a guidance cut for the same reason, and the stock was down 28.4% as of 11:15 a.m. ET on Monday. Going from bad to worse Perion has historically relied on traffic from Microsoft Bing for roughly half ...