1. A method comprising: by one or more computing systems, receiving an indication of a first user action by a first user; by one or more computing systems, when the indication is received: analyzing content of the first user action; determining a topic of the first user action based at least in part on the analysis; determining whether the topic is trending; determining whether the first user has indicated a preference to exclude posts associated with the topic or a category associated with the topic; and in response to a determining that the topic is trending and there is no indication of the preference, then: notifying the first user that the topic is trending; identifying a second user action by a second user that relates to the topic; determining whether the first user has indicated a preference to exclude posts associated with the second user; and in response to a determining that there is no indication of the preference, sending to the first user information associated with the second user action with a graphical user interface (GUI) element configured to enable the first user to interact with the second user action.