Any business without physical inventory that can be automated in a way to sell/buy should really worry about Google. Eventually Google will come for that market as their new crop of managers/execs will want to make the number to get their bonus and move up the ladder.

I know a guy who used to work at tripadvisor years ago. At the time Google was trying to start up their own hotel search business but they didn't have the reviews. So Google was initially using reviews submitted to tripadvisor by tripadvisor's reviews. I believe there had been prior agreement for Google to use tripadvisor's reviews for a fee/beter-search-ranking in return? Anyhow, tripadivisor didn't like what was happening so was in the process of telling google that they will stop the arrangement.

And a google exec in the meeting threatened tripadivisor execs that google will lower tripadivisor in the search results, if tripadvisor did stop the arrangement.

This bit was apparently shared in a regularly scheduled company wide meeting.