Everyone who has worked with Microsoft Office in the past knows the paperclip office assistant 'Clippy'. I think most of us had a love-hate relationship with this, sometimes annoying, feature. The Office assistant was first introduced in the 1997 release of Microsoft Office, and it was removed as a feature in Microsoft Office 2007. Altough most users experienced the feature as annoying and intrusive, there is actually some really nice science involved!
The origin of the feature was started in 1993 with codename Lumiere. The goal was to study and improve human computer interaction using Bayesian Probabilities. They wanted to create a way to infer or predict user goals. As software in general (and in this case, Microsoft Office in particular) became more and more complex, the idea of having an 'assistant' that helps you achieve your goals makes sense to me.