To use the appstore you need an Ubuntu One account. Basically, so it can customise the experience (ie reload your apps onto a new phone) to you and lets you buy

To use the appstore you need an Ubuntu One account. Basically, so it can customise the experience (ie reload your apps onto a new phone) to you and lets you buy commercial applications. Most end-users want convenience and customised experiences are a good way to go. If you absolutely require privacy then using a temporary email would be a way around it.