A user on NeoGAF has posted a picture of a hence unknown logo for something called "Sega Spectrum", see
Since the Japanese slogan roughly translates to "a new world of entertainment", rumors came up that Sega might actually release a new console. The date of the photo suggests that Sega will reveil at E3 what "Sega Spectrum" will be. Sega themselves have not given any details, as far as I know.
Here's the picture from NeoGAF: