enough volume to show up. "d programming language" is probably only used by non-users, it shows a clear spike in october 2004, july 2005, january 2007, july 2014, but a general falling trend. While "dlang" is more stable.
The cause of the biggest spike of interest, january 2007:
http://developers.slashdot.org/story/07/01/01/2041256/the-d-programming-language-version-10
