Oculus has had a sizable presence at the last few E3 shows, but the company has decided to pass on the opportunity for E3 2017. A spokesperson confirmed to GamesIndustry.biz, "We will not have a booth at E3 - we're focusing on the awesome games and announcements we'll share throughout this year."
At last year's E3, Oculus had a chance to demo its (at the time) upcoming Touch controllers along with several titles. But now that Touch is out on the market with a library to support it, and the company made a fairly strong effort to talk about its plans and upcoming slate at GDC back in March, it's understandable that it might want to hold off on the somewhat large investment that operating an E3 booth entails. Furthermore, while Oculus itself won't be displaying games at a booth, you can be sure that the Rift platform will see plenty of VR action at various publishing partners' booths.
It's also worth noting that this year's E3 marks one of transition for the industry event, as the ESA previously announced that it will be selling tickets to 15,000 fans for the first time in the show's history. Some, like Electronic Arts, have opted to once again hold their own events (EA Play) instead of paying for a booth. That said, it's unclear if the ESA's decision to partially open E3 to the public had any bearing on Oculus' decision for this year.