swimkidsdad,
I respectfully challenge your thought above, it is not our experience at all. One of the premier academic and swim programs in the US was recruiting our D two years ago. We visited unofficially in the Spring of junior year, and the head coach mentioned to us that they receive an average of 150 to 200 emails everyday from swimmers that are interested in their program. Their assistant coach in recruiting had taken a week off to attend a wedding. No one had touched the emails to their program during that week, and it took about 2 weeks to clear them out afterwards.
My view is that once personal contact is made with a coach–and they KNOW your email address–then what swimkidsdad says is correct. But I think it is quite easy to have your first email (or your second) get lost in the shuffle of college coaches lives. Most recruiting coaches are young and inexperienced, and organization is not their strong suit.
I still say, the squeaky wheel (polite and gracious but relentlessly determined) gets the attention, especially if your times are within range of the team.