7. The method of claim 1 , wherein the new term is associated with a classification of terms, from among a plurality of categories of terms, each classification of terms having a privacy budget.
7. The method of claim 1 , wherein the new term is associated with a classification of terms, from among a plurality of categories of terms, each classification of terms having a privacy budget. 8. The method of claim 7 , further comprising: determining whether there is a privacy budget available in the classification; and storing the new term and differentially private n-grams in the sample buffer of candidate terms in response to determining that there is privacy budget available in the classification associated with the new term.