Advanced users may choose to enable or disable certain characters from being processed by the index engine. By default, most printable characters except for punctuation are indexable, and most non-printable characters are treated as delimiters between words.
Users should be wary of changing which characters are marked as delimiters. For instance, marking punctuation characters as indexable would prevent the index engine from recognizing words adjacent to a punctuation mark. On the other hand, one might benefit from disallowing certain characters. For example, if '/' is a delimiter, the indexer will not recognize "OS/2" as a searching value.
Other reasons for tuning the character delimiters include index size. For instance, if users of the web site are unlikely to search for numbers, then marking the number characters as delimiters would make sense, since it would reduce the size of the generated index.