You only search whitelisted sites, which removes a lot of the SEO and blogspam from the results, and makes the index is wildly smaller. Search is free, but users can also pay a cheap subscription for the ability to flag sites as spammy, submit sites they think are missing, and submit queries the site has trouble with. Someone manually goes through the top N most-repeated submissions each day (early on this is all of them) and determines whether to tweak the whitelist.
Because your initial audience has to be people who are very enthusiastic about better search results, you should identify what they're interested in and focus your efforts on initial whitelists to things they care about. That might be technical questions (MDN StackOverflow, every random framework's docs site), or maybe whatever it is journalists would want to have access to (I'm not qualified to answer).
I don't think VC-encouraged hypergrowth is possible with the above strategy, but you could probably get to ramen profitable in a reasonable time frame, with slow growth ever after.