these days i see the trend where websites are offering the user to chose one of his openid to login to the website instead of creating a new one. it saves the harddisk space for the websites and users have one less account to handle. Even answers.onstartups.com follows this model.
what are its pros and cons?
is it not used to show advertisers(or investors)how many registered users you have or your customer base? there must be some use of it thats why most of the websites insist on users registering a new account with them.