I have several flights to FLA which i am having Yapta track. Last night i looked at them on YAPTA and YApta had several of them tracking at 375. When i tried to book them through YAPTA, which brought me to delta- the flight was almost 800. This happened with several choices of the flights and even though the yapta price said "checked 2 mins ago" it kept showing the 375 price but delta's price was still 800! I know yapta cant be right all the time, but this happened with 4 flights. What's up with that? the whole point of yapta is to accurately track flights.

are you sure you had the same fare class?

yes, and it's still showing the lower rate !

I've been tracking a flight to Rome from Montana and Delta was the cheapest @ $1275. I decided to let Yapta track. Nothing went down for a couple weeks. I also check ITA trip planner on a regular basis.
Lo and behold, one fine day ITA had Delta @$797. I immediately went to the Delta sight and bought tickets.
It wasn't till 5 days later that YAPTA showed a price reduction and then only down to $890.
I always have preferred ITA!!

I just tried ITA and it showed the trip i want using northwest and delta at 521. When i tried to book it, it came in at over 700. These sites are very frustrating.

Keep trying. I've found that ITA occasionally has the lower fare before the airline publishes it on the net.