This is an interesting change by Google to try to do more w/ Profiles.  To date most users’ Google Profiles have been evolved from the variety of personalized services they use from Google (gmail, Blogger, gtalk, Google Finance, etc), rather than something they’ve intentionally created or curated.  But whatever you may think of Google giving preference to their own products in search results, this won’t fundamentally “kill” Facebook, LinkedIn, or others even if a large number of Google users start populating their profiles someday.  It might put a small dent in organic search traffic for these services, but it’s highly unlikely to put any of them out of business.

Why?  First search is a jumping off point not a destination.  Yes some searchers will now click on Google Profiles because Google has prioritized them over other results.  But often if a user is searching for a person’s name, they might be trying to find their info on another SNS or their blog or whatever (i.e. a “recall” search).  They’ll probably still click thru to another site if that’s indeed what they’re looking for.  

Secondly, context and content matter in how people present their personas.  If you google “Lee Hower” you’ll come up with a bunch of things which might include this blog, my LinkedIn profile, my Facebook profile, my bio on the Point Judith Capital website, etc.  Each of those pages represents a different context, with some overlapping but mostly unique content.  Might most users somedate populate their Google Profiles to include all of this information?  Conceivably, but even if Google gets high user participation, it still probably won’t be an end all be all profile simply because most people want to have somewhat different presentations of themselves in various online contexts.  

Third, for certain contexts the social graph will matter.  If you’re trying to find out who we know in common or what my “influence” level is based on how many twitter followers I have, Google Profile probably won’t be very useful.  

When Google started prioritizing it’s own Google Maps/Local info of local businesses over a year ago, many speculated that it would be the end of services like Yelp particularly since Yelp’s early growth was driven in large part by SEO.  Yelp’s growth hasn’t exactly been killed by this move, at least in part for the reasons above.  Plus… as much as we all love Google, there are a non-trivial number of consumers out there who don’t want to rely on them for everything.