What actually happened was that, if a user had Bing's search bar installed in IE, the fine print for the toolbar installation declared that the keywords and links that they click on from other search engines could be sent to Microsoft's servers.
From the article:
>We gave 20 of our engineers laptops with a fresh install of Microsoft Windows running Internet Explorer 8 with Bing Toolbar installed. As part of the install process, we opted in to the “Suggested Sites” feature of IE8, and we accepted the default options for the Bing Toolbar.
So, the toolbar would send keyword, url, ie. {"alsdkjfsd","example.com/alsdkjfsd.html"} to Bing's crawler. Bing's crawler would include that in their search index after crawling it. Perhaps the rank of the page in the search results was included as well. This was a way for Bing to discover unindexed pages.
One could argue that that it's scummy but legal, and that the user also technically owns the data of ("what I searched for", "what URL I visited"), rather than Google being the exclusive owner of that data, and could send that to third parties. That could be a reason Google did not take legal action over it.
Google's IE toolbar also sent a ton of data to Google.
https://searchengineland.com/turning-the-tables-on-the-googl...