While there is a standard way to do that (<a title="Hit this!">a link</a>), you might want to

• make the popups come up directly without delaying 2 seconds or so because the user wants to know what is behind that link immediately
• style those popups your own way (this is mine), not that peculiar yellow the browsers use for that... and you want to do it the CSS way.
• make sure the popup is always positioned within the visible area of the browser, even if you put a lot of content in it.

I spent some time on this and update it regularly based on user comments (see below). You are invited to "steal" the code!

• A very nice and talented crowd of roughly 160 people. It was very well-organised, many thanks to the team who made it happen.
• Python has come a long way. I learned that Python detected the latest, scientifically sensational, Supernova explosion and will command an on-board camera in a robot on Mars in 2016.
• "Mr. ipython", Fernando Perez, gave an insightful keynote talk. He showcased a new kernel-clients model in the upcoming ipython 0.1.1. Not only can several clients work on the same ipython process, a client can now be anything ipython users ever dreamed of (or didn't even know they should be).  First, Fernando showed a console emulation window written in QT. It had nice syntax highlighting, tex support, actually working multi-line editing and inline plots. Pretty neat. Then he showed a broser implementation, merged last tuesday, which they call the ipython notebook. Basically, the ipython session becomes a document, which is editable inline and at all times and can contain many content types (he easily inserted images, videos, math and javascript). The whole book can be saved as json. Fernando closes with the sad fact that less than 30 people do 80% of the work in many python scientific computing libraries (scipy, matplotlib, numpy, etc).
• I presented my simulation framework Nicessa on a poster and decided to give a short lightning talk about this vision of independent layers which seem to evolve in this community (Nicessa can be the middle layer):
• On the train ride back, I happened to sit next to Ralf Gommers, one of the few major SciPy contributors, by coincidence. Pretty interesting, not only because I actually started using SciPy in a research project very recently.

Hans-Peter Dürr (interview is in German) is an accomplished quantum physicist and explains how from that point of view, "Wirklichkeit" is a much better term than "reality". He then talks about how he fought in World War II, worked with Edward Teller and Werner Heisenberg and met Hannah Arendt, leading him to later engagements for peace, more sustainable communities and economies.

Jeremy Rifkin (talk is in english, with convenient subtitles), one generation younger, is someone who runs think tanks, advises the EU on energy planning and sells books. His latest theme is the "empathic civilisation", and here he is invited at Google to explain it and the challenge it faces during the coming energy crisis. He uses the occasion to tell Google what role he thinks they should be playing. He introduces the empathy-entropy paradox we need to break: As mankind has widened the circle of empathy, the energy footprint became worse and worse.

When we use a common good, we cause the most expense and anger when we all use it at the same time. An idea that is now being tested in several places is to convince a small percentage of people to deviate their usage of the good from this popular time points. It is generally agreed that in many cases,  a change in the behaviour of very few people can already relieve a system of much pressure.

The current consensus seems to be that the system operator should pay people for that. If someone actually has the flexibility to deviate, the opportunity to earn or save money might make him actually identify and use it.

I see this in electricity markets, where demand peaks can maybe avoided by convincing a couple of devices to stop operating for a while and also in traffic management: The city of Utrecht plans to pay a commuter €4 per workday if he doesn't use the highway A2. They will have to devise some solutions where they film the numberplates of passing cars, but building new streets might be much more expensive (not to mention how much trafic jams hurt the economy and the mental wellbeing of commuters).

This can be a very effective way towards more efficient usage of common goods - but there are hurdles like the increasing hunger for usage data that comes along with it. Not many people will like that and we will need to talk about this. The good news is that if the mathematicians are correct, not everyones flexibility is needed.

Update: The Netherlands now plan to tax highway usage for everyone via satellite by 2012 (like the Germans already do for trucks). This system is more flexible, but also harder to accept.

On dutch motorways, the control system sometimes imposes tempolimits (say, 70 km/h or 50 km/h) on parts of the roads in order to prevent traffic jams further down the road. So the system knows about congestion problems in the vicinity of you, and might slow you down so you do not make a traffic jam out of it.

Recently some scientists modelled the problematic public transit system in Mexico city. Though buses run according to a plan, they sometimes stay in the stations longer (e.g. when a lot of people have to get in) and so they built up irregularities over a day, which ends up in a lot of buses being in one place and none in most others (this problem even has a name: "platooning"). They concluded that buses should just leave after a short time and not let all attending passengers board. Those passengers left out should take the next bus and overall, in the long run, everyone is better off because the whole system will run smoothly.

All this is true, but from the local viewpoint of the user of such a system, it feels wrong. I cursed when I rode on the dutch motorways and had to slow down for no reason that I could immediately apprehend. And it will definitely suck when a bus driver just leaves with you still standing right in front of the bus stop. We would hate those bus drivers.

I can tell from my own experience in understanding such systems (while researching them) that it would be hard to make everyone understand the situation. On the one hand, it's based on a lot of information and that information is decentralised - it is not all in the same place as a local observer. On the other hand, our brains are also bad at processing such abstract stuff like the platooning problem.

What to do? Would humans be happier with problematic systems, simply because they would feel more in control? Or can we evolve a system thinking in our culture that appreciates such complex, decentralised solutions? Maybe it would help to put out as much information as possible about how these systems work so that everyone can look it up herself. Maybe we'll need to go the extra mile and also visualise them really well. We should have graphically appealing real-time overviews of traffic situations (already in the making), public transports, elevators, electricity grid congestion and so on - for everyone to see and to discuss.

But I also think that in the end, not every optimisation procedure can actually be accepted - it needs at least to be understandable to stand a chance.

Neben dem Erzähler ist auch die Hauptfigur, Detektiv Brenner, eher so ein Drum-Herum-Typ, so daß es schon eine Kunst ist, wie dann später immer alles wieder zusammenkommt.

Dieser Roman spielt in Wien (schön, daß ich nun ein paar Ecken dort schon kannte), und zwar im testosterongeladenen Rettungsdienstmilieu. Da stecken sicher ein paar Wahrheiten drin...

• One important message is that societies are actually fragile and often collapse. Many seem to neglect that. Civilisation is not a one-way street uphill.
• It is actually filled with interesting facts about collapsing (Easter Island, Mayas, Greenland Norse, Rwanda, etc.) and successful (e.g. Japan) societies, as well as currently endangered (e.g Australia)
• Diamond has a 5-point framework to address the problems of societies, but here is an even shorter take-home message: Two types of choices have been crucial [for societies]: Whether they employed long-term planning and if they had the willingness to reconsider their core values.
• This book spent some time on the shelf because I found the introduction about Montana to fact-filled. If you read this, skip what you find boring. That's ok.
• Diamond gave a 16-minute TED-talk on this. Disregard the combover and that he didn't bring slides, he is a 70-year old-school professor :)