I just made a conversion search on google for "15lbs in kg" and first hit is http://www.trueknowledge.com/q/what_is_15_kg_in_lbs
I can then change 15 to ANY number, including decimals, and i always get trueknoledge as first hit with a direct link to their site for converting that number.
I can imagine that you can build up something like this fairly easy by automatically linking to the next number on every page and they also seem to do this by providing "questions like yours"-links. For this example it's quite easy but i've seen many other cases where you search for something arbitrary only to hit another search page that provides their own crappy search results for that exact search-phrase.
Is this just based on generating links by guessing phrases to provide for googles crawler or how is it done?
I'm not interested in creating a clone of these sites, i truly hate them. I'm just curious on how it's made and if google is trying to prevent it in some way. For the conversion where they provide a good result i don't mind, but when i get to another search-page it's really annoying.