I HAD MY GOOGLE PROFILE before I discovered Google had a dedicated spot for profile information. My profile was important when arriving at immigration checkpoints because several times the back office staff used Google to check up on me after arriving places where I overstayed my visa. My passport name differs from the name and nickname I carry around the internet so it's good to be Googled at the counter and validated as a nice man. Google is attempting to capitalise on every nice man's ego-surfing routines by allowing people to nominate stuff for their profile. This comes with a risk because if you compromise your Gmail log-in details, anybody with a grudge (or friends with too much time on their hands) can attribute to your name compromising photos that aren't yours, job summaries you would never write, or living locations you wish to deny. So if you've ever used any Google property with a log-in sequence tied to your real name, you need to be very careful with your user name and passwords. The first lesson I learned on Facebook is that people appear in places they'd rather not and they're put into those places by people who tag them with identifying details when they shouldn't. For added comfort, get a Google identity that in no way intersects with your real identity.
When Google profile first appeared, I lost my Yahoo! details for logging into Google's YouTube, couldn't see Google Docs unless I used a Gmail address and disappeared as a Yahoo! customer in all of Google's web services. It also meant that when I update a status in one place on Google, that status often updates in other spaces on Google.
You can trust Google not to give away private info like your phone number unless you've explicitly granted permissions for that. You can befriend people with Google Profile, so I've set up family and workgroups.
One big detraction of this amalgamated data is that once Google starts pulling your websites onto its search results for people looking up your name, you may discover that you have a very popular blog that shows up in the first or second result--along with comments pulled from your blog advertising herpes or phone sex. That's my current battle now--killing spammers before they surface as part of the search result for folks looking up my name. Here: have a go at finding me yourself and see if I'm offering Viagra or Russian wives (both results appeared when I checked while writing this post).
via Jyri Engestrom -- "Why Google Wants You to Google Yourself" in Time magazine, 25 April 2009.