Topic: sources for data feeds in xml or json

I would like to create an app which utilizes an existing data feed.

for example a grocery list app which has the aisle numbers that items are located in, etc.

Is there an existing directory of companies that make data available as a feed online in a format like xml or json? for example in the way that amazon has a feed for affiliates?

I have been googling terms like "json data feeds" but have not found much.

just wondering if anyone had run across any good resources.

Re: sources for data feeds in xml or json

By googling 'api json': (has both JSON and XML) (has JSON)
twitter also has JSON (e.g. … _timeline)