1. A method, comprising: at a computing device having one or more processors and memory for storing one or more programs to be executed by the one or more processors, acquiring a first word set from community data within a period; selecting words from the first word set according to a frequency that each word of the first word set appears in the community data during a first group of days, determining the selected words as hot words and forming the selected words into a second word set, wherein the first group of days are a plurality of days backward from a designated day; and selecting topics from a community topic set according to the second word set, and determining the selected topics as hot topics, wherein the selecting words from the first word set according to a frequency that each word of the first word set appears in the community data during a first group of days, determining the selected words as hot words and forming the selected words into a second word set, comprises: calculating a first ratio of a word contained in the first word set according to a frequency that the word appears in the community data within a first period of time during the designated day and a frequency that the word appears in the community data within the first periods of time during a second group of days, wherein the second group of days are selected from the first group of days and does not comprise the designated day; calculating a second ratio of the word contained in the first word set according to a frequency that the word appears in the community data within the designated day and a frequency that the word appears in the community data within a third group of days, wherein the third group of days are selected from the first group of days and consists of days which are of the same day of a week as the designated day, and wherein the third group of days does not comprise the designated day; calculating a third ratio of the word contained in the first word set according to the frequency that the word appears in the community data within the designated day and a frequency that the word appears within a fourth group of days, wherein the fourth group of days are selected from the first group of days and does not comprise the designated day; calculating a hot degree of the word contained in the first word set according to the first ratio, the second ratio and the third ratio of the word; and determining words with top hot degrees in the first word set as hot words and forming the hot words into the second word set, wherein the number of the words with top hot degrees in the first word set is equal to a first preset threshold, or determining words with hot degrees greater than a first preset hot degree as hot words and forming said hot words into the second word set.