sdsearch

Based on first look, it doesn't seem to distinguish between advance purchase and refundable hotel rates.

IMHO, tracking price without distinguishing between these two is pretty useless, as you can't adjust an already-booked advance purchase rate, but that's typically the lowest, so a "dumb" hotel tracking site will simply keep telling you that the advance purchase rate is lower than the refundable rate you booked.

It also is goofy about brands. It lists tons of different Hilton family brands, but lists no Marriott family brands other than Marriott proper.

Finally, it makes a difference what site you look up a hotel on. Unless you're after a Best Rate Guarantee, you want the rates from the chain's own site (so that you'll earn points/etc for the stay). Or if you want the best price at any website, you want it to check all websites, but yapta does not seem the most thorough aggregator out there.