It’s been nearly a decade since the tagline “don’t be evil” was attached to Google in a Wired magazine profile. Google, a little more than four years old, adopted the phrase as a code of conduct as it navigated through a growing list of hard questions, and as it increasingly shaped the Web itself. Since then, the term has been hurled back at its founders again and again — every time a saucy blogger or disgruntled user had a bone to pick with the company.

Google’s executives have long since stopped saying “don’t be evil” in public, and the company has been more willing to make bold moves that court controversy (as long as they lead to changes that will promote further growth). Case in point: Last month, Google altered its search results to favor pages from its Google+ social service over other social sites.

Facebook responded by designing a browser extension called “don’t be evil” that played up results from non-Google+ social sites, like Facebook and Twitter. It was an amusing potshot at Google — but for the wrong reasons. Facebook’s track record at focusing on its users’ needs and preferences is even worse than Google’s. Beyond the privacy snafus that flare up regularly, Facebook has designed its site not to make it easier for us to share content with our friends, but to weave corporate brands and ad campaigns into those friendships.

But Facebook’s exercise in highhanded hypocrisy was revealing for another reason. At some point, tech companies bled “don’t be evil” dry of any true meaning. It’s a dead motto, and its sole remaining function is as a ruler to slap the Google brand. In 2012, evil must be a part of your stock and trade. How else will you make billions in profits in the Web industry? Google and Facebook can snipe at each other all they want. But they both follow the same credo now: Let’s all be evil.

But what exactly do we mean by evil? The word can be traced back to the Bronze Age as a disparagement, but evil as we talk about it today can mean anything from an annoyance to extreme moral wickedness. And most of the evil things tech companies do don’t quite rise to the level of evil — it’s just bad. Tweaking your search results to promote your social networks is bad. So is confusing your members when they try to protect their privacy. You take a step toward moral wickedness when you let countries decide how they want to censor tweets. And you’re pretty much on your way there when you poison your workers with neurotoxins in the name of manufacturing efficiency.

In the still-nascent world of social networks, though, things could be worse. The problem is we’re already on our way down. The most powerful companies are designing their sites not to improve the user experience, but to try and get the better of each other.

Facebook and Twitter have declined to let Google incorporate their data feeds into its search engine (those companies say the data is available on the Web; Google says their terms of service don’t allow this). So Google responds by favoring Google+ in its search engine, and downplaying Facebook and Twitter. Very well, point made. But how does this help the rest of us?

In tossing aside its stated mission as a neutral search engine, Google is bowing to some strong outside pressures. Advertisers are shifting more ad dollars to Facebook, which is doing all it can to keep its members inside its walled gardens. So Google changes its search engine to lure more people into its own social site. But it risks lowering its standards to Facebook’s level, becoming a site more devoted to ad dollars than people. And slowly, what was once the Web’s public commons is turning into a collection of gated communities.

The better approach is simple, and one that has worked before. All posts and updates created by the users of all sites — provided that they willingly choose them to be public — should be available to be aggregated by any other site. From there, let the best aggregator win. That was how the Web once worked, when companies designed their sites to improve the experience for the people who use them.

It’s not that way anymore – Web companies are more interested in beating each other, even if it means a race to the bottom. Instead of enticing us with useful, intuitive design, Web sites are focused on corralling us inside through manipulation. It’s not clear whether Facebook or Google will win this game. What’s more clear is that the rest of us are losing.