18. A computing system for identifying comparatively trending topics, comprising: one or more processors; a memory; an input configured to receive, as post parameters, one or more parameters that distinguish social media postings; a transceiver configured to obtain, based on the received post parameters, two groups of posts; a group builder configured to: generate a first ranked list of topics for a first group of the two groups of posts by: identifying, as first group topics, topics from the first group of posts wherein members of the first group topics each comprise one or more words; and computing a first rank score for each of the topics of the first group topics; and generate a second ranked list of topics for a second group of the two groups of posts by: identifying, as second group topics, topics from the second group of posts wherein members of the second group topics each comprise one or more words; and computing a second rank score for each of the topics of the second group topics; a ranked topic list creator configured to associate, with a selected one of the first group topics, a difference score computed as a difference between: the rank score for the selected one of the first group topics from the first ranked list of topics, and a corresponding rank score determined based on the second ranked list of topics; and a comparatively trending topic identifier configured to: compare the difference score to a specified threshold; and in response to determining that the difference score is above the specified threshold, identify the selected one of the first group topics as a comparatively trending topic.
18. A computing system for identifying comparatively trending topics, comprising: one or more processors; a memory; an input configured to receive, as post parameters, one or more parameters that distinguish social media postings; a transceiver configured to obtain, based on the received post parameters, two groups of posts; a group builder configured to: generate a first ranked list of topics for a first group of the two groups of posts by: identifying, as first group topics, topics from the first group of posts wherein members of the first group topics each comprise one or more words; and computing a first rank score for each of the topics of the first group topics; and generate a second ranked list of topics for a second group of the two groups of posts by: identifying, as second group topics, topics from the second group of posts wherein members of the second group topics each comprise one or more words; and computing a second rank score for each of the topics of the second group topics; a ranked topic list creator configured to associate, with a selected one of the first group topics, a difference score computed as a difference between: the rank score for the selected one of the first group topics from the first ranked list of topics, and a corresponding rank score determined based on the second ranked list of topics; and a comparatively trending topic identifier configured to: compare the difference score to a specified threshold; and in response to determining that the difference score is above the specified threshold, identify the selected one of the first group topics as a comparatively trending topic. 20. The system of claim 18 wherein the input receives the post parameters by: receiving a first subset of the post parameters with corresponding parameter types; receiving an alternate parameter with a specified type matching one of the corresponding parameter types; and creating a second subset of the post parameters with of the parameters of the first subset except for the parameter of the first subset with the type matching the specified type replaced by the alternate parameter; and wherein the two groups of posts are selected by: selecting the first group using the first subset of the post parameters; and selecting the second group using the second subset of the post parameters.