Search: how to lock-in

Nicholas Carr concluded search is a commodity. There is little one can do about that. Carr mentions only three tricks:

• Embed a toolbar on the desktop.
• Personalize, the way Yahoo! works My Search 2.0.
• Embed the search engine in a portal.
  

I suppose one could think of a few more ways:

• Marketing: boast your index size. Google quit doing this, apparently after having been leap-frogged by Yahoo! in August.
• Advertising: probably a last resort.
• Relevancy, for both organic (algorithmic) and sponsored results. Google so far is winning this game. Personalization + AI could add to this. By the way, Google has its Personalized Search also.
• Loyalty points: maybe a strategy for the future.