Unobtrusive, realtime notifications of new RSS entries

Question

First, why I ask: Now that reputation points on StackOverflow have real value (you can spend them on damn good answers by offering bounties) I'd like to monitor questions I might be able to answer and pounce on them! (Also the fact that others answer my questions in real time makes StackOverflow amazingly handy, so it would be nice to reciprocate.)

To ask this as a more general question, not specific to StackOverflow:

• What kind of delay will there typically be in an RSS feed vs polling and scraping?
• What's a good way to display the notifications in a not-too-distracting way, such as Growl on Mac? (It should also be easy to turn on and off, if it does get too distracting.)

(Or, for StackOverflow addicts, what's your setup for pouncing on new questions and can you generalize it for monitoring other web content in real time?)

Answer 1

What kind of delay will there typically be in an RSS feed vs polling and scraping?

That depends on what sort of caching the site uses for its RSS feed. On SO there is no noticeable delay on most feeds, but you will need to poll the feed every minute or so. A program can not automagically get notifications from the site itself unless there is some sort of ping service on site in question.

Answer 2

You could use the service at notify.me as a slightly more obtrusive version of an RSS reader. It monitors a feed and sends you e-mail alerts. But with the basic StackOverflow setup you'd probably be overwhelmed by notifications even if there were just a "questions with bounties" feed, because there are many bounty offers per day.

So maybe combine that with Yahoo Pipes and build a filtered subset based on the information that only contain subjects you're interested in answering. Each entry in the SO RSS feed has a "category" node which contains all of its tags, and Pipes would allow you to build AND / OR / NOT expressions based on those categories. (and I don't know what other attributes might be exposed?)

Even if you don't want the pop-up notifications you get with e-mail, the Pipes solution will let you monitor what you want in an RSS feed. I'd guess that you'd see about an hour or two of lag, though.

Answer 3

In regards to question #1:

Make it as short as you like. If whatever you are using to get the feed correctly supports ETags and HTTP Cache-Control you should be fine. If you control both the server and the client, maybe checking out Delta Encoding (RFC 3229) would be a good idea.

Answer 4

Butcher an open source reader to turn on/blink your scroll lock LED.