laggard

laggard \LAG-erd\, adjective, noun:
1. a person or thing that moves too slowly or falls behind
2. falling behind; slow
Michael Greve adds an additional consideration: "Experimentation is quite probably preferable to a federal 'reform' that might get it wrong, rob the reform states of their just rewards, and discourage laggard states from experimenting with their own, possibly more effective reforms."
-- National Review Online, 12/20/2004
Microsoft claims hundreds of millions of Web e-mail and instant messenger users, but is still seen as a laggard when it comes to understanding the Internet.
-- Associated Press, The Arizona Republic, 11/12/2008
Early adopters would be on the left, the big bulge in the middle is the majority in the middle or the mainstream and the laggards are all the way on the right.
-- Dr. Grupta, CNN.com, 9/10/2007
by 1702, from lag (v.) + -ard