Have I mentioned that I take requests? Today Sandy leaves a comment for me, asking me to explain the economics of RSS feeds; I'm happy to oblige.

The comment keys off my description of FT.com's decision to truncate its RSS feeds as "idiotic". Why so, asks Sandy – aren't blogs an ad-driven medium? Don't you need to visit a web page to see its ads? And doesn't truncating an RSS feed force people to visit the web page in order to read the whole thing?

The answers to those questions are yes, yes, and yes. But.

First, it is possible to put ads in RSS feeds, and no one I know objects to them. Indeed, the future of ads in RSS feeds helps to explain why Google thought that it was worth spending $100 million to buy Feedburner. But it is true that at the moment, these ads are neither particularly sought-after by advertisers, nor are they particularly clicked-on by readers. It's fair to say that ads served and viewed on a web page are more valuable than ads served and viewed in a feedreader.

Second, there are lots of reasons beyond ad revenue why people might want to write and publish blogs. Fred Wilson, for instance, makes money from his blog despite having no advertising on it: instead, it helps him find investment opportunities. Most of the top econobloggers are tenured professors who use their blogs basically as a high-level economics seminar. And so forth. But yes, if you're talking about blogs on the likes of FT.com or Portfolio.com, I'm quite sure that the publishers are going to want to see as much ad revenue as possible from all those pageviews.

So if web pageviews are worth more than RSS pageviews, and if a truncated feed sends readers from the RSS feed to the web page, isn't a truncated feed a no-brainer?

Not at all. In fact, there's very good reason to believe that a full RSS feed will end up driving much more traffic to the web page than a truncated RSS feed will. Mike Masnick of Techdirt puts his finger on one part of the reason why:

In our experience, full text feeds actually does lead to more page views. Full text feeds makes the reading process much easier. It means it's that much more likely that someone reads the full piece and actually understands what's being said -- which makes it much, much, much more likely that they'll then forward it on to someone else, or blog about it themselves, or post it to Digg or Reddit or Slashdot or Fark or any other such thing -- and that generates more traffic and interest and page views from new readers, who we hope subscribe to the RSS feed and become regular readers as well. The whole idea is that by making it easier and easier for anyone to read and fully grasp our content, the more likely they are to spread it via word of mouth, and that tends to lead to much greater adoption than by limiting what we give to our readers and begging them to come to our site if they want to read more than a sentence or two.

And Robert Scoble says something similar:

RSS lets people read about 10 times the amount of content than if you just use a Web browser. That’s why journalists, connectors, bloggers, geeks who care about productivity, etc use RSS. It’s also why advertising in RSS isn’t yet working. These people aren’t good targets for loosely-targetted advertising...
So, how does anyone make any money?
Well, let’s stay in TODAY’S world. In today’s world you get journalists, geeks, bloggers, connectors, to read your content and link to it. That’ll bring a larger audience to visit your Web page. How do you do that? Serve out full-text RSS. Why? Cause by doing that you treat the connector with the most possible respect and give him/her the easiest way to consume your content and link to it.

It's undeniable that RSS users love full feeds and hate partial feeds – to the point at which we will tend to skip over the partial feeds even if we don't unsubscribe from them entirely. When Megan McArdle started blogging at the Economist, I subscribed to her feed. When she left, the feed remained – but I think I've actually clicked through and read the blog exactly once since then under its new author, because the feed is so truncated as to be all but useless.

More generally, I'll skim through all manner of stuff in a feed reader that I'd never read on a web page. Entries are just easier to read when they're cleanly presented in a black font of my choosing on a white background with no annoying colors and graphical elements. So if you want me to read your stuff, serve up a full feed. And you do want me to read your stuff, because if I do then there's a good chance I'll link to you, and that will drive traffic your way.

There are other reasons to serve full RSS, too. For one thing, most feedreaders allow their users to browse content offline. I been known to catch up on quite a lot of blogs while on a train or a plane. And you can't do that with truncated feeds.

What's more, nearly all feed readers have a search function, and people use their RSS readers to search for stories they're interested in. Their search term is much more likely to come up if you serve a full feed rather than a truncated one. The FT should certainly know this, because they do it themselves. Here's a little something they published back in April:

Which led blogger Felix Salmon to note that investment banks are now primarily valued for their ability to bring their own risk appetite to the table. “And they’re not just taking on senior debt, they’re taking on equity bridges and even outright equity risk,” Salmon writes.

The URL they used to link to me is very, very long. It's not a direct link to my blog; it's not even a link to Feedburner which redirects to my blog. Instead, it's a link they pulled off a blog search they did in Bloglines.com, searching on the terms KKR and "investment bank". If I hadn't been serving the full version of my blog, my blog entry would never have come up in their search results, and they wouldn't have linked to me. But they did, and my website got extra traffic – even though the FT themselves never actually visited it.

So if you want to maximise your advertising revenues, you want to maximise your traffic. And the way to do that is not to put up barriers which stop people from reading you or finding your stuff. Rather, the best way to do that is to get inbound links. And a full RSS feed will generate many more inbound links than a truncated RSS feed will.

Amy Gahran understands:

Partial feeds are popular with media organizations and others who measure success primarily by counting pageviews on their sites. That is, they think it's more important to lure people to their site so they can count them and increase their online ad rates, than it is to build loyalty by finding better ways to serve online communities on their own terms.

Even if truncating RSS did increase pageviews, it would still be a bad idea: as Jeff Jarvis says ad nauseam, what publishers are really selling is their relationship with their readers, more than easily-quantifiable eyeballs. And so they should be trying to make that relationship as good as possible.

In any case, publishers should stop thinking of websites just as websites, and start embracing all of the rest of the internet – not only HTML but also XML and anything else that will bring their content to their readers.

But the real reason why truncating RSS feeds is idiotic is simply that it's stunningly self-defeating. I used to read Slate a lot; now, I don't, because I've moved from the web to RSS, and Slate hasn't. Likewise, the FT's Alphaville blog. Hell, I'm even unlikely to notice Portfolio.com content, if it doesn't turn up in one of the RSS feeds, and one of the reasons why I'm sometimes bad at responding to comments here is that I don't have a comments feed to keep me up to speed.

I'll admit to being something of an outlier when it comes to RSS usage. But we RSS outliers are precisely the people that the likes of FT.com want to attract. They'll work it out eventually, I'm sure.