Surface Web

The Surface Web is the the part of the Internet publicly available, like this wiki. This comprises about 2% of the whole Internet. Most sites you will access in your life are a part of the surface web. However, the surface web is tiny compared to the Deep Web, with the surface Web containing only 167 terabytes of data unlike the Deep Web, which is estimated to have about 7500 terabytesof data.

Search Engine Indexing
The companies who make Internet search engines commonly send out special programs called spider programs to index important websites. The programs are given sets of criteria, and when activated find websites fulfilling the criteria. These websites are then indexed so that they appear when a user uses the search engine to search.