Nintendo will not be having a press conference at E3 this year....

And then there were two. Speaking at an Investor Conference in Japan, Nintendo president Satoru Iwata revealed that the company would not hold its typical E3 press conference at the Nokia Theater in Los Angeles this June.  Mr. Iwata said:

"Unlike previous years, we will not have a large-scale presentation [at E3] directed to everyone in the world. Instead, we are planning several smaller events focusing on software for America. Among these hands-on events will be one for American distributors and another for western media.”

Mr. Iwata disclosed that Nintendo does not plan to introduce any new hardware at E3, but the company is still expected to showcase a new Mario Kart, new Super Mario Bros. and finally reveal Super Smash Bros. Wii U.
How Nintendo will showcase those games is still an open question. But one thing is for sure:  Nintendo doesn't appear to be interested in competing head-to-head against Sony and Microsoft, who will both showcase new console hardware at their respective briefings.

Ahh this kinda sucks, I always love watching E3 and having the old Nintendo vs Sony vs Microsoft conflicts about who did better on the night.

Makes sense tbh. Even if they had new hardware to showcase they would still get largely ignored with the interest over Sony and Microsofts upcoming offerings.