Semantic Web at Opera

It is with regret that I say good luck to Kjetil in his new job, and that I am grateful for the work he has done at Opera over the last couple of years. May our paths cross again.

As a sort of delayed good-bye present, the SIOC submission that he worked on, along with people from other companies and organisations, has been published by W3C, along with some interesting comments on SIOC by Ivan Herman.

People would be aware that we already have some of this infrastructure in place. Unfortunately with Kjetil moving on, I suspect our progress will slow down for a while. He is a hard man to replace. But any comments or feedback on what we have done right, and where we should be looking to go now, is welcome and will be taken into account as we carry on...

"Things should be as simple as possible, but not simpler" -- Albert Einstein

I'm happy that quite a few people have mapped their tags, more than I expected! Now, many things are somewhat complex by their very nature, sometimes you have deal with complexities to make things that are useful. And even more often, the question is who or what should deal with the complexities. When I created the tag mapper, I realised that there would be conflicting goals, and now I'd like to discuss them with you:

For some terms, you will see that there is a dropdown under "Relation" that contains both "topic" and "depicts". The "depicts" is there when the term is a noun, and the idea is that when a tag is used for a picture, then you can say that the picture depicts a dog, for example. So, it is a way to very directly express that meaning.

Doing it this way would also create really simple SPARQL queries, to get all pictures that depicts a dog would amount to (ignoring the namespaces):

    SELECT ?pics WHERE { ?pics foaf:depicts <http://www.w3.org/2006/03/wn/wn20/instances/wordsense-dog-noun-1> . }

That's about as simple as these queries get.

Also, as I mentioned, the plan is to use tags for content labels, and since I'm Opera's representative on W3C's POWDER working group one of my main concerns is how people can easily tag their content with content labels on sites like Opera Community. Again, the easiest would be if a content label could be directly associated with a picture. For example, we have to live with a certain amount of nudity in the pictures our users upload since we don't want to exercise censorship, we just don't want to push it on random visitors, and we want to facilitate parental control, and that's one of the things content labels will be used for: A standard way to say that a picture contains nudity.


This is made possible by a slightly more complex user interface. Arguably, it would be easier to just map your tags, not also having to decide if it depicts something, or if it points to a content label. If we didn't do this, it would be harder to formulate the SPARQL queries, but more importantly, this would only be the beginning, since you're clearly using the same tag not just for pictures, but also for blog posts, and you wouldn't say that a blog post depicts something. So, for this to really work, we would need different relation types depending on the type of resource, whether it was a picture or a blog.

That's where it gets nasty.

So, I'm wondering if the course I've started out on is unworkable. Perhaps the relationship from a tag to a term like the Wordnet terms should be unchangeable? That would make the user interface simpler, but the queries and other uses would be harder. So, it isn't just a question what's the simplest, rather, it is a question of who should deal with the complexities.

Now, it is important that as many as possible to participate in tag mapping. Not everyone needs to write applications or queries that uses these data, so those wishing to do so are probably better suited to deal with the complexities than all those seeing the tag setup page. On the other hand, it is quite important to make the POWDER specification quite simple too, and this use could add complexity to the specification.

So, your opinions will matter here, please bring them forward!

Then, you might ask, dear guinea pigs , why I made a complex user interface to begin with, and then ask if I should make it simpler? Well, clearly, I couldn't start discussing this with you if I didn't show you a complex user interface that worked, it would be much harder to explain what I had in mind. So, I figured I might as well do a little research on you. The experiences gain from this is something that will be used to make the right decisions when designing important standards that will be with us from many years to come, and I feel it is important to get this experience now, before those standards are set.

The Semantic Web Education and Outreach Interest Group has published a small questionnaire with the intent of gather programmers around a few practical ideas, to create some applications that will make a real difference in people's lives.

The Semantic Web community has quite a few good programmers, and many have produced some cool demos of the technology. Also, many have been working on really big and advanced projects for years, and it is just starting to bear fruit. There has, however, been few times where we have gotten together with the goal of producing something useable quickly.

I wrote this questionnaire as a beginning to correcting the situation, as I believe it is important for the acceptance of the Semantic Web. My own, little pet proposal is also to use FOAF networks to ensure that emails from your friends will reach you even with aggressive spam filtering on. So make sure you continue to build those friend networks here on the Opera Community, it may help you in fighting spam soon!

People ask from time to time what you can do with widgets. Although you can make a "Hello world" widget (the instructions fit on a business card) it seems that this is a little simplistic for most people. Instead they make a clock widget.

Beautiful as some of these are (mine, for example ) they are not in themselves the thing the world needed most. But every so often something comes along that has real value. I think the first semweb widget was Jibberjim's Widgnaut, a widget version of foafnaut that crawled My.Opera's FOAF data. (Since we added the possibility to link your My.Opera FOAF to external files, it isn't a walled garden, just a starting point. Kjetil++! ).

Today we released a new widget - the tabulator widget version of Tim Berners-Lee's tabulator, which is a generic RDF browser. This means that now available for your delectation, an RDF browser running in Opera. I'm waiting to see how it works when widgets are released on mobile browsers, but please, get Opera 9 (or 9.01) if you haven't already, download the widget, and give it a try.

Many thanks to David Håsäther who did the widgetising and debugging to make it work cross-platform, Tim and all the folks who have worked on the tabulator project, JibberJim for building the RDF parser in the first place (way back when) and Gorm for making that work in Opera too.

I gave a lightning talk about Perl (the programming language that underlies most of Opera Community) and RDF on the Nordic Perl Workshop. That's a very short talk, just to give participants a short overview. My slides are available.