AMP is correct if we're only analyzing standalone SE's with their own proprietary dbase and technology.
However, if an adult webmaster wants to start a search engine aggregator site featuring cobrands/"private labels" of Overture [formerly GoTo], and other paid per search sites, these are fairly easy to setup since you're using someone else's database and they are PAYING YOU to do it.
For an example of "private label" SE's try
http://mojosearch.com
they pay webmasters $$$ to use their search boxes
{Look Ma, no ref codes!
}
NOTE: Promoting your SE is going to take a lot of hard work. However, some scumbags [which will go unnamed since they've been named in other boards] use SSI to "hide" scripts that change surfers' homepages and bookmarks to point to their private label SEs.
Good Looking Out and I wish you the Best!
LinkyD