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.