Human powered directories are special types of search engines, organized into subject categories. The directories are smaller than most search engines and do not contain full text of the webpage they link to. Such directories are good when a user is interested in a general topic of search.
Crawler based search engines such as google .com HUman powered directories and Hybrid search engines
Dmoz is the best example. It is a high quality directory which needs manual approval to get any site included in the directory.
"Why are you a nuclear powered human being?"
So far, there are no practical human powered helicopters.
Castro powered light car
A rickshaw
Invention Nation - 2007 Human Powered - 1.12 was released on: USA: 2007
There are 3 types of search engines:Crawler-based search engines: These search engines, such as Google, create their listings automatically.Human-powered directories: A human-powered directory, such as the Open Directory Project depends on humans for its listings.Hybrid search engines: Hybrid search engines will favor one type of listings over another. For example, MSN Search is more likely to present human-powered listings from LookSmart. However, it also presents crawler-based results, especially for more obscure queries.
rickshaw
They are all human powered.
Invention Nation - 2007 Human Powered 1-12 was released on: USA: 2007