Google is gearing up for classifieds as they are now looking for a "Vertical Markets Director, Classifieds" described in this job posting. A classifieds service similar to Craigslist.com could raise enough excitement to create the biggest "sell your stuff" craze since eBay. Not to mention it will bring Google closer to the ultimate goal of all big Web companies -- being "the source" for everything and reaping the huge amounts of advertising revenue that comes with it. Google's classifieds service cannot be far away as a similar product offering from Microsoft (Fremont) is on the way.
As with most Google services it will be completely ad-funded, and in the long term could severely hurt (or at least change) companies like eBay who rely on listing fees and commissions. Without paying to list their items, sellers will flock to this ad supported service -- and buyers are sure to follow, especially if Google duplicates the user and buyer features and trust (rating) elements that have made eBay's trading/auction network work. If Google is successful in making this service a part of life -- as they have done with Google Search -- they will dish themselves another huge slice of ad revenue.
It's not just about classifieds though -- a network effect is at work that encompasses all other current and future services like mail, calendar, froogle, classifieds, local, analytics, GTalk/VoIP, etc. It's about the eventual goal of being "the source" -- a place and brand where people can go for their online needs and play out their digital lives. If Google can produce highly useful integrated services, they will unleash a large amount of ad and subscription revenue from users who have become as integrated into their services as the services themselves. It's a kind of walled garden, which Yahoo, Microsoft and AOL are also building, that lets some things in and out, but maintains just enough of your online persona to make it inconvenient to switch services or brands.
A missing link is "Google Purchases". It could potentially be integrated with almost all of their current services in one way or another and cement Google's relationship with its users in another dimension. You could find yourself using Google Purchases to buy talk time for your GTalk VoIP account or purchasing items on a classifieds service. It could be integrated with Froogle to give users an easy and secure way to buy items from merchants and act as an escrow service at the same time.
Right now, Google has only one primary means of generating income (AdSense/AdWords) and there is no telling if the growth engine can continue at the same pace in the future. If the competition can successfully convince advertisers to "make the switch" or Google somehow has a trust issue with its millions of adherents, Google's juggernaut is at risk. It's all about getting users to trust and subscribe to the Google solution. Its competitors are in the same waters, just paddling different boats, but for now Google is perceived as the king of the online sea. But, the seas can be stormy and no company is immune from changes in the weather or the loyalty of users.