1. A method of automatically modifying text displayed on a graphical user interface by detecting offensive words in a string of words transmitted over a computer network, comprising: receiving and storing in a computer database, using one or more processors, a plurality of offensive words, wherein each respective offensive word in the plurality of offensive words is associated with a severity score identifying the offensiveness of the respective word; receiving a string of words, using the one or more processors, wherein a candidate word is selected from the string of words; calculating, for each respective offensive word in the plurality of offensive words, using the one or more processors, a distance between the candidate word and the respective offensive word, the distance between the candidate word and the respective offensive word being a value on a scale having more than two possible values; calculating a plurality of offensiveness scores for the candidate word using the one or more processors, each offensiveness score in the plurality of offensiveness scores based upon (i) the calculated distance between the candidate word and an offensive word in the plurality of offensive words and (ii) the severity score of the offensive word, wherein a particular offensiveness score is based on a product of two terms, a first of the two terms being based on the calculated distance between the candidate word and a particular offensive word, and a second of the two terms being based on the severity score of the particular offensive word; determining, using the one or more processors, whether the candidate word is an offender word based on whether the highest offensiveness score in the plurality of offensiveness scores for the candidate word exceeds an offensiveness threshold value; and when the candidate word is determined to be an offender word, adjusting the candidate word, as stored in a computer-readable memory, prior to display of the adjusted candidate word on a graphical user interface.