A method for assigning a topic to a collection of microblog posts may include, by an acquisition module, receiving from at least one messaging service server, a plurality of posts, wherein each of the plurality of posts comprise post content; by a generation module, analyzing the posts and extract, from at least one of the posts, a link with an address to an external document; and, by the acquisition module, accessing the external document that is associated with the address and fetch external content associated with the document. The method may also include by the generation module: analyzing the post content to identify at least one label for each post, for each post that includes a link, analyzing the external content to identify a topic, and using a topic modeling technique to generate a trained topic model comprising a plurality of topics and a plurality of associated words.