Purple numbers: Useful but unrealistic

Written by Adrian Holovaty on June 2, 2004

Gaining attention lately is the idea of purple numbers -- a way for Web-page authors to make each individual paragraph on every page throughout their sites directly linkable. The idea is that each paragraph has a distinct URL and, thus, can be cited directly.

Influential technologist Tim Bray first tossed around the idea last week; then Simon Willison followed up with a somewhat elegant solution to the problem of how to display the paragraph-level hooks to which people should link; Mark Pilgrim took the idea to its logical extreme; and Chris Dent compiled a bunch of links to various people's comments. Already a few weblogs have implemented the paragraph-level linking scheme, using purple-pound-sign links as hooks after each graf.

I don't plan to implement purple numbers on this site yet, if ever, mainly because I'd rather not litter my pages with distracting post-paragraph links (initially visible or not), but I point it out because it's an interesting idea news-site maintainers should know about. Would there be value in being able to link directly to a particular paragraph in a Washington Post story -- say, a telling quote or a provocative fact? Probably. Would it be worth it if, in the process, it confused millions of people who didn't know why they'd started to see purple pound signs all over the place? Probably not.


Posted by Gary Love on June 2, 2004, at 9:13 a.m.:

The purple numbers project seems to be jumping the gun on a good idea. I've fallen into the same trap with some of the promises of the semantic web myself. It is not suprise that some people would want to link together multiple pieces of content seamlessly, no matter where they are published or maintained.

Unfortunately, that future isn't here yet. XPath and XPointer are graceful solutions for the problem of linking together content no matter where they exist online (or on a page), but they can't be used on websites until HTML transitions to XHTML and is delivered as valid XML.

I think more than anything, the purple numbers idea is sign that we're moving in the right direction with the Semantic Web. If enough people want this type of functionality bad enough, maybe they'll be willing to go through a little of the hardship to get us there.

Personally, I'm hoping that Mark Pilgrim's cuddly bear standard wins over the ugly purple numbers.

Posted by Philipp Lenssen on June 2, 2004, at 9:59 a.m.:

I did something similar on Authorama, where I give readers the chance to view every paragraph of the books a single page, as well as leave a comment to it.

We also have to think of search engines. Google does not understand how to display a search result of only one paragraph. Search engines do not consider inline-links; they might in the future.

Ideally the Web needs linking and comments to work independent of a site's implementation and a webmaster's strategy. Our browser itself should be the tool for us to edit a page (if we have the rights), leave a comment for others to see (if they want to see it), or jump right into the middle of a page to a paragraph (if that is the intention of the link we were offered).

Posted by Rikard Linde on June 4, 2004, at 1:53 p.m.:

Direct links to weblog comments would be a good start. I rarely see them and yet they can be so useful. Just a thought.

Posted by homer jay on June 9, 2004, at 10:54 p.m.:

Don't we already have this?


Maybe I'm missing something...

Posted by Gary Love on June 10, 2004, at 8:49 p.m.:


Yup, that's how the purple numbers work.

In order to target href="#myParagraph" a name="myParagraph" or an id="myParagraph" needs to exist somewhere on the page. The purple numbers are just a standardized way of adding and displaying links to those paragraphs.

Posted by -jas on August 12, 2004, at 8:54 p.m.:

The point that Homer Jay is missing is that to get

href="#myParagraph", the author of the work had to put it there.

What happens when the author does not put links in place?

By using a tool that does it semi-automatically, the document gets this link.

And then you can reference it, without the author having to do the hand work

of generating unique id's for each paragraph.

And for people who are without purple tools like PurpleWiki, there is

PurpleSlurple, which will apply purple numbers against any document.

With these tools you get an operational way to reference inside a document.

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