[1zee]

You know people that would not recognize any of those brands?

[losteric]

FWIW I've heard of one of those (Kayak), plus Priceline - and I only used Priceline a few times in college (they turned me off of using these tools).

[titanix2]

Yes, beside Booking.com I never heard of any of them. They may be a thing in the US, outside not really.

[wott]

I only know Booking (never used it personally, but my relatives do; well... did, I think they stopped for ethical reasons: the 'middlemen' thing), I've never heard of any of the others and I have no idea about what they provide.

[baddox]

Do they advertise on TV? If they do, then there's a decent chance my parents (in their 60s) know about them, otherwise it's very unlikely.

[michaelmrose]

I had only heard of kayak out of the lot.

[ksk]

I recently met an older dude who hadn't heard of Craigslist!

[vwcx]

There are all kinds of people who have never heard of Craigslist within the United States. There are also plenty of children under 18 who have never heard of Craigslist. Despite its popularity and relative staying power, Craigslist belongs/belonged to a specific sub-generation.

[frgtpsswrdlame]

Plenty.