"Currently, this account can be used to access Google Web API and Google Answers. In the future, your Google account will enable login access to all Google services, including Google Groups posting, Google Adwords, the GoogleStore, the Google in Your Language program, and more."
It makes sense to regroup all your user preferences in one place. I for one would like to store a list of favorite Usenet newgroups and posts I want to track. Right now you don’t even logon to Google Adwords and Google Adwords Select from the same page.