KEY TAKEAWAYSShares of ServiceNow are tanking 9% in premarket trading Thursday, as the software and IT services provider posted slower subscription revenue growth than it had forecast earlier and projected a slight decline in first-quarter growth.The company reported higher-than-estimated fourth-quarter adjusted earnings per share and revenue in line with estimates from analysts polled by Visible Alpha.ServiceNow shares have surged almost 50% in the past year through Wednesday. Shares of ServiceNow (NOW) ar ...