Full Text Search
Full text search is what Google does for web pages. It's different to term matching because it tries to respect language, grammar and tense. For example, matching search term run with documents containing run, running and ran.
It doesn't match terms exactly and instead makes use of
- stemming : finding a common base word so differences in tense, plural/singular or other inflection are still matched, and
- stop words : removing words such as and, or, it and maybe that occur too often to search over.
Note the difference if
alloftext is changed to