The Note Search rolls up information to the Note level by default. This means that if a Note is created against more than one Organisation, the search results will show "..." under the 'Organisation Name' column.
Likewise, if the Note was created against more than one Contact, then the "Contact Full Name" column will also show "...".
Users also have the option of choosing 'Show one row per Note' and 'Show one row per Contact/Organisation Association' from the 'Result Behaviour' menu in the top left-hand corner of the Notes Advanced Search page. Selecting the second option will return all Note - Contact - Organisation associations, so you will see all Notes and each Contact / Organisation it is linked to.