A pun on Naughty by Nature's song "OPP", "OPIP" has recently taken on the meaning of "Other people's IP". As in, "Other people's IP addresses." It's quite common recently for people to edit Wikipedia, for example, from an Internet Cafe (coffee bar, etc) and exclaim, "Ahh... OPIP."
"Hey, you want to edit that Wikipedia page? OPIP, baby."