Totally agreed. I also lost a little respect for Hipmunk when I found out they are basically an exact copy of ITA's app: http://matrix.itasoftware.com/search.htm.
ITA's app doesn't seem nearly as useful to me for a few reasons:
1) The form at the beginning is much more confusing. Creating a search with Hipmunk is much less complicated.
2) Flights are ordered by price, whereas Hipmunk orders them by "agony", which in my experience, seems to be pretty accurate.
3) Doesn't default to time bar mode, like Hipmunk does.
I wouldn't at all fault you guys for taking advantage of the coverage. I'm just wondering why the HN crowd decided to give free advertising to a small incremental update.
This does give a compelling reason to join YC, though: plenty of cheerleading around YC startups.
Hipmunk is great and all, but I fail to see how a travel site adding an icon is relevant to the HN frontpage.