1 Good start! Now let's add some linked data to the

Mark,

Very nice introduction – my new favorite RDFa introduction!

How about the linked data aspect? We’ve recently started to flesh this out [1]. I guess it would make sense to do more here in this area, together. What do you think?

Cheers,
Michael

[1] http://ld2sd.deri.org/lod-ng-tutorial/

posted at 09:53 am on June 23, 2009 by mhausenblas

2 Small reflexion

You have not really made it clear what the real purpose of RDFa is… I don’t really understand what would be the advantage of defining metadata inline…

It seems like we always tend to try and seperate different categories of data; as web developers, we can seperate data from markup (XSLT), we can seperate content from styling (CSS) and we can seperate content from action (Javascript), for instance. Having inline metadata reminds me of the days of inline CSS… ~shudder

Now I understand the need to target specific parts of the content with additional machine-readable information, but there should be a way to do so without having to clutter up the beautiful, clean, concise markup. Something like an external metadata file?

I think RDFa might be suitable for a restricted number of projects such as mentioned in the article (Youtube, Yahoo…) but it still has this experimental feel to it. I don’t think the technology is really up to par with the common coding practices of the semantic web.

What do you think?

posted at 10:35 am on June 23, 2009 by epgui

3 RDFa / Microformats: which is better?

hey there, thanks for the article!

i have been coding with MFs for some time now, and am wondering, you mention that Yahoo! “has been processing RDFa for about a year”, but you don’t mention anything about MFs with them, are they not bothering with MFs, or have they specifically sided toward RDFa?

other than possibly that, any real strength of one over the other?

i would rather not have to code BOTH into my mark-up, and, while i have no allegiance to one or the other, i guess i would lean toward MFs, just because i already kind of know them…

thanks,
Atg

posted at 10:52 am on June 23, 2009 by Aaron Grogg

4 @epgui

RDFa/MFs are simply to provide better “semantic” value to your mark-up, meaning, to give users (be they human or bot) a better explanation of exactly “what” the data is, not just what is “says”…

a date is, i think, the easiest example, and i can think of few people that do a better job of explaining MFs, specifically, than Jeremy Keith:
http://adactio.com/journal/1579

another great example of the power MFs/RDFa can bring to the web, check out these guys:
http://visitmix.com/Lab/Oomph

cheers,
Atg

posted at 11:10 am on June 23, 2009 by Aaron Grogg

5

@epgui: Most authors do not create separate, semantic views of data such as RDF and RDFa allows them (and authoring tools) to add machine-readable attributes to their HTML documents and these attributes are part of the content, rather than presentation or behavior; this becomes more important as content (pieces of documents, such as images) gets shared and remixed across sites and pages.

@Aaron: Microformats provide a similar approach, but they are design patterns (based on defined vocabularies such as dates, contact information, etc.) whereas RDFa enables authors to use an existing vocabulary or create a new vocabulary to describe anything in a semantic manner.

posted at 11:28 am on June 23, 2009 by davidlantner

6 Of course

I understand the value of microformats… However, I think the current syntax for highlighting semantic data is not appropriate for a world wide web standard.

Maybe I am missing the point, it’s just that I don’t like the idea of having all that metadata inline, in the body of my markup. I can see how it would quickly become very unnessecerily cluttered on a very regular project, say, a blog.

I could see that the benefits of the technology for internet bigshots (again, like Youtube, Google and Yahoo, for instance) would largely outweight the inconvenience…

I am not one to define web standards, but I am thinking that an external metadata file would be very nice. I would guess it could be easily done with an XPath-like syntax for selecting nodes for which to specify metadata. The whole thing could be just an external XML document.

I am unaware whether or not something similar already exists.

I don’t know if that was more clear of a thought =P

posted at 11:31 am on June 23, 2009 by epgui

7 @davidlantner

Right! You have a very good point, didn’t think of that. A technology like RDFa would prove to be very useful for content that is to be shared across domains or services.

I’m sure there are also other advantages!

posted at 11:34 am on June 23, 2009 by epgui

9 How many browsers support it?

Microformats is supported by Safari, Firefox (with plugins). Is there any such support for existing RDFa vocabularies? Will these RDFa attributes be valid HTML 5?

posted at 12:29 pm on June 23, 2009 by Divya Manian

10 RDFa vs Microformats

First off, great article!

Definitely helpful in distinguishing RDFa from microformats. I’ve only recently started using microformats and have been a little fuzzy on the differences, pros/cons, etc. between the two.

For those wanting more info on microformats, I highly suggest reading Emily Lewis’ series on microformats:
http://www.ablognotlimited.com/articles/getting-semantic-with-microformats-introduction/

I am looking forward to part 2 of this RDFa primer.

Thanks again,

Jason

posted at 07:04 pm on June 23, 2009 by jnakai