Highly recommonded: the podcast of Joshua Schachter’s talk at the Future of Web Apps Summit

He drops a lot of useful information on lessons learned while building del.icio.us, but I was mostly impressed by his takes on balancing del.icio.us within the ecosystem of the Web 2.0, e.g. (notes from Simon Willison):

growth

As the population gets larger, the bias drifts; del.icio.us/popular becomes less interesting to the original community members. Work out ways to let the system fragment in to different areas of attention.

tags

Tagging is mostly user interface – a way for people to recall things, what they were thinking about when they saved it. Fairly useful for recall, OK for discovery, terrible for distribution (where publishers add as many tags as possible to get it in lots of boxes).

Automatic tags lose a lot – doesn’t help the user really achieve their goals. That’s why the ‘add to del.icio.us’ badges don’t let you suggest tags.

Value in Delicious is in the ‘attention’ – auto-tagging detracts from this.

‘Beware librarians’ – some people want to give tags a specific, underlying meaning. Don’t let them.

the selfish user

‘You have to understand the selfish user’ – user #1 has to find the system useful or you won’t get user #2. Systems that only become useful when lots of people are using them usually fail, because there’s no incentive for people to contribute themselves. The real trick is to make the user base you have want to invite more people in to the system.

Goals skew the results. People don’t read, they cram crap in to boxes. Let people wander don’t give them tasks.

morals

You have to develop a sense of morals when you build your system. It’s the user’s data; it’s not yours. Make sure they can remove themselves and their account if they want to.

In del.icio.us if a user deletes something they really do purge the data from the system. No transaction logs etc for getting stuff back.