topr8 - 11:16 am on Sep 7, 2010 (gmt 0)
... i think this is one of those situations where just because everyone else is doing it - it doesn't make it right.
the way i look at it from my own personal experience is that i can never remember my password and log in info at a later date, so it is a waste of time - sure i can for amazon, but i shop there a lot, am i going to shop from you a lot or not?
in several years of ecommerce where i do get repeat customers i've only ever had one person message me a bit annoyed that i didn't have a log in system that remembered all her personal info.
i also think that there is a privacy timebomb waiting to explode - especially if you track peoples movements through your site and associate those movements with personal details (not tommorow, but one day)