Multiple Brands instead of Multiple Levels of Service
patio11: I don't think it is a good choice for the generic web startup with 2~4 levels of activity.  If you're pitching the different levels to totally different markets, I could see it.  (Example: Heroku versus Big Freaking Enterprise-ku.)For startups that don't have that severe of a segmentation between the needs of the different tiers, it sounds like a way of time and money.  Your maintenance needs just increased proportional to the number of brands.  (Easy to implement?  gah  I shiver at thinking about it.)Want to do an A/B test?  Enjoy writing it four times, and potentially ending up with 4 different optimal choices that you have to maintain for forever.You also split your link equity -- 4 domains with 1,000 links split between them won't rank nearly as well as 1 domain with 1,000 links pointed at it.  Because search is a Winners Take Most game, it won't end up with each of the domains having 25% of what they could have, it will be closer to .01% of what they could have.