In MagicPositioner, you need to set at least one target site, as every operation is linked to a target site. Since it is a fully automated process, it's easier to find the sorting criteria to optimize page ranking.
Directories also collect data in quite the same way, so a similar optimization can prove useful.
The difference is that there are people working for directories who surf the web and store data about the pages they find interesting. Moreover, as pages are organized by categories, you have to choose well in which one you want your site to appear. Measures the correspondance between a web page and a request. The closer to the request the page, the higher its relevance. Designates the action of making a request to a search engine, and keeping the results.