5. The method of claim 1 , further comprising: selecting the one or more of the second terms based on a second score value, wherein the second score value is produced with steps including the following: (a), receiving a second group of text units containing the one or more second terms, at least half of the text units in the second group are selected from random sources, or selected using a random selection method or its equivalent, or not selected from a predefined or specified document class or category, or selected from more than ten different classes or categories or topics for this purpose, (b), for the one or more second terms in the second group of text units, producing a cumulative value based at least on the number of text units that contain the second term, and (c), producing the second score value based at least on dividing the cumulative value by the at least half of the total number of the text units in the second group of text units.
5. The method of claim 1 , further comprising: selecting the one or more of the second terms based on a second score value, wherein the second score value is produced with steps including the following: (a), receiving a second group of text units containing the one or more second terms, at least half of the text units in the second group are selected from random sources, or selected using a random selection method or its equivalent, or not selected from a predefined or specified document class or category, or selected from more than ten different classes or categories or topics for this purpose, (b), for the one or more second terms in the second group of text units, producing a cumulative value based at least on the number of text units that contain the second term, and (c), producing the second score value based at least on dividing the cumulative value by the at least half of the total number of the text units in the second group of text units. 6. The method of claim 5 , further comprising: producing a third score value, wherein the third score value is determined based on the difference between the first score value and the second score value, or based on the square of the first score value divided by the sum of the first score value and the second score value.