As said in my first post, I found six sessions in parallel quite overwhelming. Thus, I - as all other visitors - only could attend a little fraction of the talks.
I enjoyed the contribution of Florian Alt who proposed a proxy-based implementation  to alter the content of website with or without the owners consent. This could increase usability of badly designed sites or, probably more important, to implement dynamic applications on static content, e.g. integrating infos from your social network with content of a website you're just looking at.
Next I fascinated by the simpled idea Paul Holleis  presented to attach a sequence of NFC tags behind a laptop screen in order to fascilitate touch-based interaction similar to a touch screen but at much lower cost. Obviously, one technically problem to be solved is to find screens that still allow the radio waves to permeate the screen.
Finally, I was glad to see the talk of Felix von Reischach , our Ph.D. student, presenting our work about the different ways of interacting with mobile devices and products: barcode vs. epc vs. nfc.
 F. Alt, A. Schmidt, R. Atterer, P. Holleis
Bringing Web 2.0 to the Old Web: A Platform for Parasitic Applications. Interact 2009. Uppsala, Sweden. 24-28 August 2009.
 Khoovirajsingh Seewoonauth, Enrico Rukzio, Robert Hardy and Paul Holleis. NFC-based Mobile Interactions with Direct-View Displays. Interact 2009. Uppsala, Sweden. 24-28 August 2009.
 F. von Reischach, F. Michahelles, D. Guinard, R. Adelmann, E. Fleisch, A. Schmidt: An Evaluation of Product Identification Techniques for Mobile Phones, Full Paper at the 12th IFIP TC13 Conference in Human-Computer Interaction (Interact2009), Sweden, August 2009, [PDF] [Talk].