TechXtra is one of the best deep web search engines where you can search for content that has to do with Math, Engineering, and Computing. You can search for things such as technical data, industry news, classifieds, learning resources, full-text Eprints, and relevant website information. There is the deep web and the deeper dark web. The internet is just one of the networks that comprises the world wide web. An outdated, but still useful network is Usenet, which is accessible with a newsgroup reader, and contains text newsgroups, as well as binary newsgroups.