The spider returns all that information back to a central depository called a data center, where the data is indexed using advanced algorithms. The spider then periodically returns to the site to check for any information that has been altered or added. The frequency with which this happens is determined by the administrators of the search engine.

Human-powered search engines rely on people to submit information that is subsequently indexed and catalogued. Only information that is submitted is put into the index. This technology is similar if not exactly like the original search engine databases. Companies like Dmoz™ still work in this fashion. This technology still has a place in certain situations when trying to focus on specialized information.