Digital marketing and e-commerce company Cox Automotive Inc. will buy Dealertrack Technologies Inc. in an all-cash deal worth about $4 billion. Atlanta-based Cox Automotive focuses its services on the automotive industry. Among its properties are Kelley Blue Book, Manheim and Autotrade. Lake Success, N.Y.-based Dealertrack makes software used by the auto dealerships. The deal values Dealertrack at $63.25 per share, marking a 61% premium from its closing price of $39.19 on Friday. The companies expect the deal to close in the third quarter. Dealertrack shares climbed $23.13, or 58%, to $62.98.