The following information was put together using information taken from the homepages of the named search engines. The statistical and server information in particular aren't provided as a performance comparison, but rather to be viewed just as informational. Search terms With most search engines a sub-string search is implemented, with some a genuine part word search or exact search is possible. In the case of Open Text regular expressions are also allowed.
Some services also offer weighting of search strings.
Excite weights a term according to frequency of appearance in the search request. With Open Text the weighting value can be given. Excite also offers a concept search which uses a thesaurus so that the search term doesn't necessarily have to appear in a document. Some search engines offer various search modes. Additionally, Open Text offers weighted searching as the distinction.