I am building a web service that involves parsing of 3rd party RSS feeds. How can I be informed about the 3rd party RSS feeds being updated?
I know that I can set up a Cron job to check for RSS updates every X minutes. But I don't want to generate unnecessary traffic and computing overhead.
Can I somehow have my system pinged by a web service like Pingomatic or FeedBurner?
Unfortunately RSS on its own does require polling -- no "push" or "pub/sub" available. pubsubhubbub aims to remedy that -- though both the RSS feed supplier and the RSS feed consumer will need to support it before it's any concrete use to you.
I believe Pingomatic only pings one or more of a predefined set of search engines (it doesn't ping your own web service, as it doesn't know about it -- maybe you could arrange some commercial agreement with the pingomatic folks to change this?) and similarly Feedburner "pings" specific sites such as digg -- I don't know of an API for either service (or other similar services) to change that.
do you know http://superfeedr.com ?
they do exactly what you ask for and it's free for 1000 feeds