Shane Greenstein says Bing is behaving legally, but not ethically:
Bing imitates Google: Their conduct crosses a line, by Shane Greenstein, Virulent Word of Mouse: Imitation happens. ... Slate.com installs a better tool for soliciting comments, and a month later the same feature shows up at the Huffington Post. Chrysler brings out a minivan and within a two product cycles every other auto assembler has one too. Nobody loses sleep over this.
Moreover, the Internet makes monitoring a rival easier, so imitation involves less hassle and far lower costs than it used to. ...
What happened? ... Google’s engineers hypothesized that users of Microsoft Internet Explorer were entering search requests into Google’s search bar and getting results. They speculated that Microsoft began using that data to tweak the Bing search engine. In short, Google’s users and answers were informing Bing’s results.
That hypothesis turned out to be right. Neither party denies it. ... Bing monitors Google by watching users...
In the modern Internet,... there is no longer any privacy for users. Providers want to know as much as they can, and generally the rich suppliers can learn quite a lot about user conduct and preferences. ...
In the offline world, such intimate familiarity with a rival’s users would be uncomfortable. It would seem like an intrusion. Why is it permissible in the online world? Why is there any confusion about this? Why isn’t this cut and dry?
In other words, the transaction between supplier and user is between supplier and user, and nobody else should be able to observe it without permission of both supplier and user. The user alone does not have the right or ability to invite another party to observe all aspects of the transaction.
That is what bothers me about Bing’s behavior. There is nothing wrong with them observing users, but they are doing more than just that. They are observing their rival’s transaction with users. And learning from it. In other contexts that would not be allowed without explicit permission of both parties.
Moreover, one party does not like it in this case, as they claim the transaction with users as something they have a right to govern and keep to themselves. There is some merit in that claim. ...
What happens now?
This looks like a classic high tech standoff. No law is being broken, so nothing can stop Bing from learning from users that go to Google’s search engine. Judging from their remarks, it sounds like they intend to keep on doing just what they are doing.
That makes me sad. The righteous reaction of Microsoft’s management seems tone deaf.
They had a choice to do it differently (and still have this choice). It would have been much more grown up for them to admit the unintended benefit they have gotten by watching their rival interact with their user. It would more ethical to swear they had not intended to benefit from a type of spying on their rival that would be unethical in other contexts. It would have been mature to then declare that they would win in the long run with good hard innovation instead of gaining advantage from this little piece of information.
(There's quite a bit more detail and explanation in the post.)