xiven.com stating the blatantly obvious since 2002

Trackbacking across the universe

Since everyone else seems to be doing it, this weblog (damn I really need to think of a decent name for my weblogging software) now has Trackback support. Having implemented both Pingback and Trackback I can now say with certainty that Pingback is much nicer.

The main problem I have with Trackback is that the embedded RDF for autodiscovery is absolutely hideous to parse (even the example code given in the spec. falls down on several valid examples) and because you need a separate entry for each post, you need to make damned sure that you are looking at the right piece of RDF. Not to mention the fact that putting data that needs parsing inside a comment (<!-- -->) is just plain wrong.

Pingback is much more sensible: firstly all you need to look for is either an HTTP header or a simple <link rel="pingback"> tag; secondly, you send the permalink of the post you are linking to in your request so you don't need to have a different pingback URI for each post on your weblog.

Pingback also has a much better written specification, which explains everything very clearly with good examples. The Trackback specification leaves out many of the details (eg. How does the server find out which post you are referring to when you send a Trackback? -- answer: you need a unique trackback URI for each entry) and has several ambiguities (eg. url: The permalink for the entry. Which entry: the one I'm sending a Trackback to or the one I'm sending a Trackback from? -- answer: it's the latter).

All of this makes me wonder why Trackback appears to be more widely used than Pingback. The only technical advantage of Trackback over Pingback is the ability to send an excerpt of the document with the Trackback request. I can see how this can be useful (I don't use it personally), but it is not entirely impossible for a Pingback server to grab an excerpt from the source page should you wish to do so.

One reason I can think of is that many people seem to be very confused about Pingback:

...the key distinction being that trackbacks are client-server and pingbacks are peer-to-peer between servers. So [this software] could support trackbacks, but not pingbacks.

I hate to say this, but that is blatantly not the case. Pingback is just as much "client-server" as Trackback is. My code for Trackback and Pingback is very similar in both the client and server aspects (the only differences being in the format that the request is sent and in the method that the autodiscovery works).

Another reason why Trackback is quite successful is that a lot of people use Movable Type for their weblogs which of course comes with Trackback built in.

Ah well, I just hope this doesn't become another Betamax vs VHS scenario...

Posted: 2003-01-18 10:24:14 UTC by Xiven | Cross-references (0) | Comments (8)




  • Xiven (Registered) (2003-01-20 15:58:46 UTC)

    And now we can post comments.

  • Phil (2003-01-21 00:52:50 UTC)

    a) Your comment box is Huuuuuuuuuuuge. You really want people to fill it?
    b) This could lead to all sorts of abuse...

    If people want to comment shouldn't they do so in their own blog and pingback a link to your blog entry? Anyone who doesn't have one of these blogs shouldn't be worried about anyway.

  • Xiven (Registered) (2003-01-21 08:39:22 UTC)

    a) No, but it's nice to have the space isn't it?
    b) Well if it becomes a problem, I disable comments and life goes on.
    c) The very topic of "are comments needed now we have pingback/trackback?" has been discussed in depth before (though I can't find any of this discussion at the moment). Basically the thing ended up boiling down to: if you're not allowing comments on your site purely on the basis that only people with weblogs should be able to make comments then you're basically saying that everyone else's opinion doesn't count. Which I'm not; therefore I implemented comments.

  • Phil (2003-01-22 01:41:22 UTC)

    I have two differing views on the topic.

    1. Comments are really an indulgance. Pingback etc is a great way to do it without getting into a debate in someone's comments. (bloody hell this box is big) It's like having comments on a news site. They tell the news, they don't really care what you think. Even this isn't a rule though as the bbc news site has a "comment on this story" feature. All of the comments, ALL of them are dumb.

    2. Comments are fun. Whilst they might upset the time space continuum in some way (we'll find out in years to come) they still make things fun. Rather than writing a weblog which rarely gets pingbacks or other weblog coverage you can interact with your readers and get a little direct feedback. Besides, if you write something funny then it's nice to get a little recognition. Besides, you can argue with friends in them about all manner of shite.

  • Phil (2003-01-22 01:42:21 UTC)

    I want to be able to edit them too. Especially when i fuck up my website address.

  • Phil (2003-01-22 01:44:28 UTC)

    I swear it just ate my last comment. Do you have a max number to display?

  • Kai (2003-01-23 06:25:03 UTC)

    Nice form. When I was reading this blog in Straw, a news aggregator, it was just one gigantic block of text. I wonder why, as I see your p tags.

    Btw, did you hear I beat Kam at WC3?

  • Phil (2003-01-23 15:23:51 UTC)

    You might have won at wc3 but you were truly his bitch at quake3. What the hell happened man? I'd hate to have no pride left.. :)