We've reached the end of day 3 at our week-long BBC Innovation Lab (photos from flickr here ), and it's been a thoroughly rewarding, absorbing, eye-opening and occasionally nerve-racking experience so far.

As expected, the latest incarnation of our project is now completely unrecognisable from it's original concept, but it's leapt up the conceptual evolutionary ladder from a primordial soup to a lean, mean, top-of-the-food-chain predator that's giving us a quite excited tingly feeling about it's potential.

Yesterday was devoted to making the idea "People-Shaped" - developing two fully-fleshed-out user personas and walking through the entire lifecycle of their engagement with the application, from discovery and first use, through to veteran user status. The key question at each interaction was "How does this make Daniel / Kelly" feel? What is their emotional response, and what does that drive them to do or not do?

This User-Centric Design day proved to be an invaluable process, and helped us to jettison several features straight away that were just not relevant, and add several more that simply hadn't occurred to us until we walked a mile in the users' shoes. By the end of day, the insights we gained had resulted in the massive evolutionary leap from a still-vague concept to a fully-formed system in our heads, one that we could visualise, wander around in, and really feel like we owned.

By contrast, today was all about making it "BBC-shaped" - making it relevant to the BBC and giving them compelling reasons why they should be the ones to fund this, rather than anyone else. Another eye-opening day, with some great feedback from our mentors and some valuable experience in pitching the concept to interested-but-skeptical parties from wildly varying backgrounds - from at-the-cutting-edge-of-it-all to others who had only really been introduced to the concept of tagging on Monday morning.

We are very proud to report that after spending three days enthusing at great length in true Headshift style about the benefits of the bottom-up to anyone who asks, we have now been banned from any mention of the terms Tagging, Taxonomy and Vector Space at dinner, on pain of.... well, pain... :)

Tomorrow is prototyping day, where we begin to focus on our pitch and the demonstrable aspects of our interfaces, so we are spending tonight swotting up on the excellent resources available from Guy Kawasaki's blog. Other reading material for us includes Presentation Zen and GarrReynolds.

Ah, curling up with a warm laptop, you can't beat it.