On Comment Feeds

Through Carthik’s post A minor debate I came across this thread talking about comment feeds. The thread is a little funky and Carthik is obviously enthusiastic, but what stood out is Anil‘s comment “If there’s enough demand from users for it, we’ll include them in MT as part of the package.” Which prompts the question, how much demand from users for this was there in WordPress? Do we just bloat the willy-nilly with every idea that comes down the line? The answer is in two parts:

First, a great deal of thought and deliberation goes into every feature we include with WordPress, particularly the ones enabled by default. One guiding force of WordPress is that every release is faster than the one before that, and to do that you have to optimize ruthlessly and be very wary of any bloat in the code. So far we’ve been very successful with this: WordPress is at least 3 times faster than b2 was and we still have added features that other systems are just beginning to catch up with. With comment feeds there is the immediate benefit of people being able to subscribe to any thread on any WordPress site in the world, but there is a further benefit of bootstrapping a technology of which the benefits are just beginning to be fully realized. Feedster can index not just every post on a WordPress blog, but every comment as well. Aggregator developers may not have gone to the trouble of supporting <wfw:commentRSS> for just a few custom feeds, but now I can point fifteen thousand blogs using it to point to a countless number of comment feeds.

The market might not be demanding a feature yet, but if you just wait for the market to decide it wants something you’ll always be following and never leading.

Second, a great idea can come from a single user. Pure numbers are a factor when considering new feature suggestions, but most good ideas stand on their own merits. Innovation usually comes from the places you least expect it. If I remember correctly we had about a dozen or so people interested in comment feeds that I knew of, but it really could have been one. It was an idea that made a lot of sense within the stated goals of WordPress and didn’t cost anything to add. Alex got the code together and it was in the next release. It’s been improved a couple of times, and now you can add /feed/ to any permalink (or category page, etc) in WordPress and get the feed you want. Users that didn’t know they wanted comment feeds before are thanking us now. Eventually all modern blog software will support comment feeds, and WordPress will have moved on to something else new.

11 replies on “On Comment Feeds”

  1. That’s actually a good point, should comment feeds be chronological or not chronological, and if they’re reverse chronologically ordered should they contain only the most recent comments or all of the comments? Personally I think they should be chronological and contain everything, which is how I have them set up here.

  2. The individual post comment feeds in wordpress are an excellent idea. I’m not a huge fan of how some blogs ‘force’ you to subscribe to all of their comments…

  3. Hmm. I happen to think that comment-feeds should be similar to regular feeds, such that the number of comments is limited and everything in reverse chronological order. Why? Because (and this is completely unscientific, by the way) that is probably easier on aggregators — they already know how to deal with this kind of feed. It is also probably easier on one’s bandwidth, if that is a concern.

    I remember being subscribed to the “I bought a Powerbook, what software should I buy” thread, through Bloglines. I did not get any of the updates through Bloglines, even as new comments were coming in. I am wondering if this is at all related to the fact that the feed lists the comments in forward, as opposed to backward, order.

  4. As luck would have it, just after posting my last comment, the Mac feed came through on Bloglines. Sigh. If you did anything to fix it, it worked; thanks! If not, blame it on my frequently poor timing.

  5. Matt: JournURL has done individual comment feeds for a couple years now. In fact, in addition to the per-thread feeds, you can also get per-category and per-community feeds, as well as search-based feeds. (And quite a few more, now that I think about it.)

    RE: bloat… I agree, that shouldn’t be an issue. Providing such feeds in my case doesn’t cost any extra queries or anything. In fact, it just re-uses existing code and spits it into a different markup package.

    RE: feed ordering… Currently, JournURL comment feeds are chronological and contain the entire thread. Although the physical order of the entries shouldn’t matter in an aggregator that respects pubDate.

  6. Oh, wow! LOL! I had no idea you could just tack /feed/ on to the end of, say, categories, or archives, and get a feed in a newsreader.

    Where are all these little tricks hidden? Certainly not the manual. 😉

  7. Hey Matt, I noticed that appending /feed and /rss both work, but while otherwise the feeds seem to be identical, the pubDate for the feed differs between them. Why is that? Is this a bug? Are /feed and /rss supposed to be identical and therefore which URL you use is just personal preference, or are they supposed to be different?

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