@Splint: Just a note, he didn't actually yell "The British are coming!" as depicted in some children's stories for a couple reasons. First, the colonists living there still considered themselves British even if they had disagreements with the British Crown. Second, he wasn't that far ahead of the army and yelling at the top of his lungs would get him captured. Eventually, he was captured anyway, but by then there were about 40 riders fanning out across the countryside.
The whole Battle of Lexington was based on intelligence failures. The British were sent to seize rebel military supplies "known" to be in Concord when they had in fact been relocated months earlier... and the Americans were responding as if the army had been sent to kill or capture the rebel leadership, which they hadn't.
Auspicious start for a country, eh?
I know that. It was more that he got the ball rolling (along with I wanna say... two other guys, wasn't it? And the alarm response grew from there as they informed patrols and others with less inclination to like the Army Regulars.)
In the end there was a massive clusterfuck either way, and it ended with a bunch of guys dead at Lexington (mostly militia,) a failed objective for the regulars, and getting shot at for a good chunk of the way back to Boston for the poor bastards. Hell, I bet the "shot heard 'round the world" was the result of some guy sneezing with his finger on the trigger. Certainly takes some wind out of the patriotic sails when you imagine your country getting started by some random guy with a cold...