According to Tweets (via CVG) made by Jonathan Biddle of Curve Studios, Valve may be getting rid of their Steam Greenlight service within the next 12 months.
We met with Valve at GDC, and they say Greenlight will be gone within 12 months. They'll still offer curated space, but otherwise be open.

This tends to go hand in hand with what Gabe Newell said a couple of months ago about wanting to make Greenlight go away as Steam evolves. This also ties in with how Valve is giving more control over games and sales to the developer instead of having to go through Valve.

Let's just hope this new "openness" doesn't mean the platform is going to be filled with even more bloat, junk, and shovelware than it already is.