Jose Reyes of the Mets became the first player in 2006 to hit for the cycle. The Mets ended up blowing their lead in the 9th inning and lost the game, but that's the unimportant piece of data. My son and I will remember this one because we watched it together, just as my father and I saw Richie Zisk hit for the cycle for the Pirates in 1974 (that was the first cycle completion by a Buc since Stargell did it in 1964). Zisk's accomplishment made Pirates fans believe that there was something special about the outfielder who stepped into Roberto Clemente's cleats. It's a rare enough event that you file away its context, so that you can place it next to other memories of value.
This is how communities are formed and exist over long periods of time; you find some shared context that binds you to the next person who shares an interest. It works for sports fans as well as non-profit and community organizations; it's the glue that holds Little League boards of directors together even as the players grow up and move onto larger fields.
The community glue is hardened a bit more when you have wikipedia on your side, of course. Within 10 minutes of Reyes' single that completed his cycle, his Jose Reyes entry was updated, as was the list of players who have hit for the cycle.