Athens.
Finally for this trust and security panel at WebSci '09 we move on to Pavlos Spirakis. He begins by noting that the Web was initially invented as a tool for researchers who trusted one another implicitly, so no security was built in from the beginning. This is no longer the case, of course, and so theer is a need fro privacy protection and for the protection of the freedom of its users. Layers of trust must therefore be engineered into Web technology.

Trust, however, is the belief of one party in another, and distrust is not simply the lack of trust, but the belief that the other partner explicitly cannot be trusted. Such distrust is an important notion in its own right, then. Trust is a relation between two parties, then, is context-specific, and exists in varying degrees of strength. This means that trust is measurable, Pavlos suggests, and that it can be expressed mathematically (algorithms such as Google's PageRank build on this).

Athens.
The next speaker at WebSci '09 (via video) is Ann Cavoukian, the Toronto privacy commissioner. She suggests that we need to think differently to protect privacy - there is a need for strong legislation and other forms of protection. but most of all privacy also needs to be embedded into technology; without privacy, she says, there is no freedom.

This may need a substantial change of attitudes amongst technology companies,but it is possible and necessary - riffing off the Obama slogan 'yes we can', Ann suggest that for this issue, it's 'yes we must', and she has been pushing for the recognition of an international data privacy day.

Athens.
The trust and security keynote at WebSci '09 is followed by a panel on the same topic, which starts with Kai Rannenberg. He begins by referencing the Internet of Things, and by way of example shows a prototype of a high-tech toilet (a washlet) that monitors the user's health condition on the basis of their, um, bodily products and reports such data to their doctor or other health authorities where necessary. Another key area of new Internet-based services is location-specific and builds on mobile devices to determine location, time, and identity of the user, and of course there is a wider range of datamining-based applications online.

Athens.
The post-lunch (mmmh, baklava) session on this first day here at WebSci '09 returns us to the question of trust; the keynote speaker is Jacques Bus, head of the European Commission unit "Trust and Security" within the directorate for the Information Society and Media. He begins by noting that we have moved from a walled fortress to an open metropolis model for digital information; this is a move from securitisation, isolation, walls, and the protection of everything, to trust, agreement, communication, and the protection of goods. In this digital world, there is as yet no adequate identity management for persons and artificial entities; the protection of data is the key.

Athens.
I'm now in the business session of this first day of WebSci '09 - it brings together a variety of Greek business leaders and politicians. The session will be in Greek, but there's a simultaneous interpreting service - we'll see how that turns out. The first speaker is the representative of the Greek Minister for Development, who points to the importance of life-long learning, the decline of distance, and new modes of working which are associated with the move to a digital economy; this is also associated with new forms of e-commerce and electronically mediated cultural activity.

Athens.
Up next at WebSci '09 is Patricia Victor, who begins by noting the growth in recommendation systems, including, for example, the advanced functionality on Amazon and in other e-commerce applications. Some 60% of Netflix users, for example, base their viewing on recommendations, and Netflix has offered a US$10m prize for an algorithm that improves its recommendation system by 10%.

There are two classes of recommendation systems: systems which are content-based and systems which are collaborative filtering-based. The latter focusses on similarities in the rating behaviour of users, and trust-based systems are often based on such algorithms. Epinions offers such a social trust network, and also allows users to evaluate other users by placing them in their network of trust, thereby conferring particular importance on these users' trust ratings. This also alleviates the 'cold start' problem with new users; it provides more reliable and accurate recommendations and leads to a kind of trust propagation through the network.

Athens.
The first full day here at WebSci '09 begins with a keynote by NIgel Shadbolt, founding director of the Web Science Research Initiative (WSRI). As we're in Athens, he begins by taking the historical approach: he notes that another way to describe Web science is as 'philosophical engineering', which links back ultimately to the founding fathers of philosophy, including Socrates, Plato, and Aristotle. Their pure philosophical speculation, indeed, formed the basis not only for modern philosophy, but also for modern science.

Athens.
The second keynote this evening is by Joseph Sifakis, who begins by taking us through a quick tour of the history of informatics - starting with Turing and Gödel in 1936 and moving through information systems, graphic interfaces, the emergence of the Web and the information society, and leading today to the increasing embedding of computing systems into all kinds of technologies. In the future, we'll see further developments in computing power and storage capacities, and this means that computing systems will be literally everywhere. In developed countries, in fact, a person already uses some 250 different processors per day - processors in cars, computing equipment, home entertainment, telecommunication systems, and so on.

Athens.
Tonight I'm at the opening session for WebSci '09, and we're looking forward to a keynote by Sir Tim Berners-Lee, on the twentieth anniversary of his invention of the World Wide Web. The conference itself is going to be opened in the presence of none other than the president of Greece, though, so the place is swarming with Greek police (unsurprisingly, given the continuing low-level unrest in the country). In fact, there's a couple of secret service agents coming through right now, earpiece and all. His Excellency himself is running fashionably late.