1. A computer-implemented method of facilitating queries of a topic-based-source-specific search system, the system being configured to collect information from predefined sources relating to a content topic prior to the queries, the method being implemented by the system that includes one or more processors executing one or more computer program modules which, when executed, perform the method, the method comprising: receiving, by a query input module, an input relating to a query; determining, by a suggestion module, suggested ones of the predefined sources and suggested ones of information items of the predefined sources based on the received input; and providing, by a user interface module, a set of suggestions including a group of suggestions relating to the suggested sources and a group of suggestions relating to the suggested information items for presentation on a user interface; providing, by the user interface module, a query input component on a display of the user interface, wherein the query input component is configured to receive the input; receiving, by the query input module, a second input relating to the query responsive to providing the set of suggestions; and determining, by an information retrieval module, a subset of the information items that relates to the received second input; determining, by the information retrieval module, one or more sources associated with the determined subset of the information items; and providing, by the user interface module, one or more representations of the determined subset of the information items and one or more representations of the determined sources on the display of the user interface simultaneously with the query input component.
16. The method of claim 1 , further comprising: determining, by a user profile module, a source set associated with a user, wherein the source set includes at least one source associated with the user; determining, by the suggestion module, second suggested ones of the predefined sources that are not included in the source set; and providing, by the user interface module, a group of suggestions relating to the suggested sources on the display of the user interface simultaneously with the query input component, the representations of the determined subset, and the representations of the determined sources based on a determination that the second suggested sources are not included in the source set.