一个开源的email与文档的索引服务，并且以web方式使用，与google desktop很像，怀
疑是google desktop借鉴filofant的，其实发现google也借鉴了不少开源的东西，但是
相对IBM还有alpha works之类的不少开源的东西与对开源的支持，google却还不那么明
显。
Webmasters looking to provide search capabilities for their site would do well to try out PhpDig, a Web spider and search engine written in PHP with a MySQL backend
This class is meant to interface with the Ht:/Dig programs to be able to index and search Web pages from PHP. It features:
- Setup a suitable configuration file from a few user defined parameters.
- Index Web pages to build the search databases.
- Search the indexed database to capture the matches into a PHP data structure ready to be used to display the results in a PHP generated page.