How do price searching sites work?

[WannaFly]

I've got a good idea for a website I'd like to start -it'd basically be a pricewatch like site but for a different industry. I'm quite fluent in programming, so I'm not worried about the code - but my question is in regards to the theory or how the sits get their prices.

From what I can tell theres a few different options:
1) Scrape sites
2) Ask for XML/Webservice/Etc feeds from sites
3) Manual input


1 would be the least (ongoing) labor intensive - but it is probably also the most initially labor intensive as each site would need scraped differently. Also, there is a good possibility of getting wrong $ amounts, etc.

2 would be great but i don't see the sites subscribing to it as it means work on their behalf

3) It's just a bad idea.

so, does anyone know how sites like froogle or pricewatch work? Lets discuss.

 

[mzkhadir]

1. A database that hold all the information such as prices and stuff that gets updated daily or by users, merchants.

2. An interface such as froogle or pricescan to interact with the database to pull up prices.

 

[WannaFly]

Originally posted by: mzkhadir
1. A database that hold all the information such as prices and stuff that gets updated daily or by users, merchants.

2. An interface such as froogle or pricescan to interact with the database to pull up prices.

I guess it makes sense - it just seems more 'automatic' then having the merchants enter the data. Obviously, the hardest part would be getting merchants to participate.

 

[mzkhadir]

Originally posted by: WannaFly

Originally posted by: mzkhadir
1. A database that hold all the information such as prices and stuff that gets updated daily or by users, merchants.

2. An interface such as froogle or pricescan to interact with the database to pull up prices.

I guess it makes sense - it just seems more 'automatic' then having the merchants enter the data. Obviously, the hardest part would be getting merchants to participate.

What froogle/google said that when google crawls the web looking for stuff, it identifies the prices and the merchants selling and adds it to the list.

http://www.froogle.ie/froogle/intl/en_us/about.html