Loopt is more successful than HN users would realize. Some of what it does isn't consumer facing, and its users are (like e.g. Stumbleupon's) mostly not HN users.

In any case, you can't measure someone by one company. The formula for the success of a startup includes a random multiplier of roughly zero to a thousand. You can see this from how common it is for successful founders' second startups to fail.

I'm actually more impressed with Sam than when I wrote that. Since then I've talked to him a lot more because he is one of the alumni working part time as YC partners. He has extraordinary energy combined with the judgment of someone twice his age.