When you have as much information as there is on the internet, any attempt to sort through it creates a bubble. At least a paid search engine allows feedback between the users and the algorithm and some confidence that the engine won't go under because the authors lost interest/got tired fighting abuse for free/etc.

The filter bubble is the value proposition. I never want to see results from spam sites like Quora or expertsexchange.

Have you seen the crap outside the filter bubble? It is trendy to call filter bubbles the well from which all sorrows are drawn but not everything is worth reading, no matter how many drink the koolaid.

This isn't scientific obviously, but I feel since I started using Kagi, my scope has widened significantly of what I rely on for results. Another +1 for what these guys are attempting.

You pay for search one way or another, I'd rather be direct about it.

You're assuming you're not already in the worst possible filter bubble: advertising incentivized curation.

It depends on what the customer base is paying for and expecting. If they expect a bubble and complain about it not being there, they'll likely get a bubble. If they complain about the bubble being there, steps will likely be taken to reduce or remove it.

For better or worse, the direction of a paid product is usually fairly well defined, as long as they've taken time to understand their customers.