1. A computer implemented method comprising: receiving information about an action performed by a user, wherein the action comprises at least one of creating or interacting with first content, the user associated with an interest graph stored in a machine readable medium and representative of interests of the user in a plurality of topics; analyzing language of the first content to identify lexical features of the first content; determining a topic of the first content based on the lexical features of the first content; and updating the interest graph stored in the machine readable medium to modify an attachment level in the interest graph representing an interest of the user in the topic of the first content.
3. The method of claim 1 , wherein determining a topic of the first content based on the lexical features of the first content further comprises: determining a topic of the first content based on the lexical features of the first content and the interest graph associated with the user.