When the Agile Manifesto hit the street in 2001, it combined several methods, sometimes called "lightweight methods," under a single banner. Scrum, DSDM, ExtremeProgramming (XP) and Crystal were all "agile" in that they matched the spirit of the manifesto. These methods enable small teams to do their best work, getting the paperwork out of the way and bringing the customer into the conversation.
The focus on "small teams" worked for small teams. Today, larger organizations want to move toward more agile methods, too. The methods they’re interested in extend the original methodologies to include larger teams, coordination and oversight. They also introduce risk; an experiment that goes wrong for the entire IT department is much more dangerous than for a team that experiments for a few months.