I just can't imagine that the name easypost was 15k better than alternative names. I get that the company already had traction and it'd be cheaper to buy the domain than change the name of the company but I guess what I'm trying to say is domain name availability should probably be the number 1 criteria when picking a new startup name.
Perhaps if Jarrett had waited until he found that perfect .com name he wouldn't have launched first, and as a result would have had less initial exposure. Less initial exposure means less initial traction, and that might have lead to easypost not raising their first round, or raising on much worse terms, both of which could easily be worth more than $15k.
On top of that, finding an available .com isn't easy. You essentially end up using a non-english word, mashing several words together, or use something like geteasypost.com (which easypost owned prior to making this purchase).
Non-english words are harder to say and recall, and could ultimately affect word of mouth growth. Mashing words together puts you in a similar situation, and nearly every company who owned get<company>.com or try<company>.com ultimately ended up buying <company>.com if they were successful. Dropbox did it. Facebook did it. Easypost just opted to get theirs earlier in the company's lifetime.
This is important how? Are these ~150 extra up votes really worth $100 each? Really worth 7.5% of your funding round. Yeah, yeah, yeah, visibility on HN is good but outside the HN bubble I think I'd rather have the 15k.
"easypostage" and "easypostapi" neglect the value of clean, concise naming conventions as a marketing advantage to what at the time ended up being a competitive market.
EasyPost was ahead of the curve in terms of acknowledging company representation. As an early pseudo-developer at Teespring, I felt very comfortable in their docs and deploying against their API. This was based on both their technical (seems consistent across YC co) and branding capacity.
Over a year and a half later, I'm not surprised by their success.