I just started a poll in the right column -->
The Founders: Pre-1974
You belong to the tiny group of people who gamed with Gary Gygax, Dave Arneson, Rob Kuntz, etc. before D&D was commercially available.
1st Generation: 1974-1977
Game: Dungeons & Dragons
Characteristics: You belong to a relatively small group that starting roleplaying with the three little brown books. These may have been blurry bootleg facsimiles, or, if you were lucky, they were originals tucked into a woodgrain or white box (shown).
Games: Basic Set (Holmes), Basic/Expert Sets (Moldvay/Cook), Advanced D&D
Characteristics: You belong to the largest generation of D&D players. You came of age in the late 1970s or early 1980s when D&D was a huge fad and sold zillions of copies. It's likely that you began playing with the Holmes "Blue Box" or Moldvay "Purple Box" (shown) basic sets, eventually "graduating" to the AD&D hardcovers.
3rd Generation: 1983-1988
Games: Basic/Expert/Companion/Master/Immortal Series, "Updated" AD&D
Characteristics: Even though D&D went through a major popularity decline in the mid-80s, new players like you continued to pick up the game either through the expanded series of boxed sets - including Mentzer's famous "Red Box" basic set (shown) - or through the ever-expanding line of updated AD&D hardbacks with the Easley covers.
Games: AD&D 2nd Edition, D&D Game, Classic D&D, Rules Cyclopedia
Characteristics: You primarily played AD&D 2e, although a small number of you may have been introduced to the game through the various basic editions (The D&D Game or Classic D&D). This was the lowest point for D&D as most roleplayers during this period favored games like Vampire or GURPS or skipped RPGs altogether to be part of the new collectible card game scene.
Games: D&D 3rd Edition (and 3.5)
Characteristics: You started playing D&D with 3e or 3.5e, probably in the heyday of the d20 open gaming license. 3e breathed new life into D&D at this time, but interest eventually started to wane due to a glut of poor quality third party products, and a confusing progression of complex rule additions, updates, and errata.
Games: D&D 4th Edition, Retroclones (Pathfinder, Labyrinth Lord, etc.)
Characteristics: You first started playing D&D a couple of years ago, most likely the 4th edition. This generation is quite different than preceding generations, however, because many new players are choosing to start with earlier editions of D&D, especially the 3.5e retroclone Pathfinder which threatens to eclipse D&D 4e in popularity.