Phillip Pearson - Second p0st

tech notes and web hackery from the guy that brought you bzero, python community server, the blogging ecosystem, the new zealand coffee review and the internet topic exchange

2003-9-2

Two ways to find things out

There are two ways to find things out. You can wait for somebody to tell you (notification), or you can go and find them for yourself (polling).

Each has its advantages. If you get everybody to tell you about everything, you don't need to do much work. But if you go and find out everything yourself, you don't need to worry about missing out on something because somebody who was meant to tell you something couldn't find you at an important time. If you sit still and wait for people to tell you things, somebody new can come and tell you about things you never knew about. If you do that all the time, you might end up spending all your time listening to crap that you didn't want to know ... but if you never do it, you could be missing out on things that are important.

Now, on to real life.

RSS is the second way: you check somebody's site all the time to see if something new is there. It involves work: you need to actually go and have a look. Your news aggregator does it for you behind the scenes, but it still must be done.

E-mail is like a blend of the two ways: when somebody has something to tell you, they send you an e-mail. Except they don't send it directly to you, they send it to your mail server. Which you check all the time to see if something new is there.

A lot of the stuff I've heard people talking about recently boils down to finding out when new things happen (or appear, or are written).

For example, in a recent post, Marc cites Don citing Richard, who complains that it's hard to keep track of stuff you write all over the web, then puts out a call to blogging tool vendors to implement per-thread RSS feeds for comments.

I implemented these for Python Community Server back in May 2002 (they can also be seen in YACCS, and apparently BlogBack and dotcomments), and they work OK, but if they ever get popular, they could cause a serious amount of bandwidth usage.

In hindsight, Manila's "Receive direct responses to the message on this page via email" feature is better. At the very worst, the server has to send an e-mail to a million people when a comment is posted. This is still better than a million people checking every hour to see if something has changed ... especially on a long-dead comment thread.

In this particular case, I'd say that a notification approach (the "first way" mentioned above) is safer here. The mechanism doesn't have to be e-mail, but I don't think RSS as currently used is the answer. If you're dead set on using RSS, a safe thing to do would be to have the site send you some sort of notification (e-mail? TrackBack to your blog? TrackBack to your personal Topic Exchange channel?) to say that the RSS feed has updated, and for you to go and check it then. But be wary of implementing something in a polling manner when it doesn't change much and may attract huge amounts of interest ...