Hi,
I was planning an upcoming trip and I needed specific flight times and airlines, and I wanted to watch the price trends to look for significant price drops (if any) but most sites only notified about price drops (usually the 'cheapest') flights regardless of airlines.
Anyway I came across this site which lets you save & watch a specific flight number for any price drop changes. I thought it might be useful for someone:
I used this site to book a hotel and can really recommend it if you have the time.
I had to choose a bunch of different hotels I was happy to stay out then got emails for a few weeks when the price of these hotels when up or down (which was several times a day so be prepared for a flood of emails) and managed to get something like 50% off at a few places.
You don't need to actually book with them, when the price dropped it seems to drop everywhere else so you can go to hotelscombined or similar and save a extra few $.
Edit: Looks like they don't do hotels anymore :(