The “Go-Go Checks” on the covers of many mid-1960s DC comic books were the creation of then-DC Editorial Director Irwin Donenfeld. In an interview published in TwoMorrows’ COMIC BOOK ARTIST, Donenfeld explains,

“In those days, comics were on the newsstands with vertical slots for the magazines. I wanted to have something that showed DC Comics were different than anything else. So I worked it out with Sol Harrison and out that checkerboard across the top. So wherever these magazines were displayed, you could always see a DC comic from way back. It was to distinguish us from anybody else.”

Comic Book Spinner Rack tells us what the go-go checks are and where we can find them:

Known as Go-Go Checks, the checkerboard pattern that ran across the top of every issue for a year and a half was not simply a reflection of the era’s pop-art movement. Since some newsstand racks displayed comics vertically, revealing only the upper portion of a book, the pattern was intended to make DC’s comics stand out and thus, theoretically, increase sales. “What a ridiculous thing,” Carmine Infantino declared. “It was the stupidest idea we ever heard because the books were bad in those days and that just showed people right off what not to buy.” But Donenfeld disagreed: “I was trying to find a way of making DC Comics pop out on the newsstand. It wasn’t a bad idea; it just didn’t work the way I wanted it to. It didn’t add anything, but I thought it might.” In fact, total sales for the entire DC line during this period were at their peak for the 1960s, sales for Batman-related titles increased dramatically, and DC was outselling all of its competitors. The checks were most likely cancelled as a waste of precious cover space, and interestingly, sales did begin to stall about a year later.

Thanks to CBR’s 365 Reasons to Love Comics blog for the info.