9. A computer system for filtering outbound content via inference detection, the computer system comprising: a processor; a memory coupled to the processor; an content-selection mechanism configured to identify previously sent content associated with a common first destination identifier; a keyword-extraction mechanism configured to extract a set of keywords from the identified previously sent content; a query mechanism configured to: issue a set of web search queries that each includes one or more of the extracted keywords to obtain a set of search results; extract a set of candidate keywords from the set of search results; an inference detection mechanism configured to perform inference detection using the set of search results for the extracted keywords; an expected-content mechanism configured to determine, from the set of candidate keywords, a set of expected-content keywords which are determined to be representative of the previously sent content based on the inference detection; a receiving mechanism configured to determine whether outbound content is proper in response to receiving a piece of outbound content with another destination identifier, which involves performing one of; determining that the outbound content is associated with the first destination identifier, and the number of expected-content keywords present in the outbound content is below a first predetermined threshold; and determining that the outbound content is not associated with the first destination identifier, and the number of expected-content keywords present in the outbound content is above a second predetermined threshold; and a display mechanism configured to display the destination identifier for the outbound content and at least one expected-content keyword present in the outbound content, responsive to the outbound content being improper.
9. A computer system for filtering outbound content via inference detection, the computer system comprising: a processor; a memory coupled to the processor; an content-selection mechanism configured to identify previously sent content associated with a common first destination identifier; a keyword-extraction mechanism configured to extract a set of keywords from the identified previously sent content; a query mechanism configured to: issue a set of web search queries that each includes one or more of the extracted keywords to obtain a set of search results; extract a set of candidate keywords from the set of search results; an inference detection mechanism configured to perform inference detection using the set of search results for the extracted keywords; an expected-content mechanism configured to determine, from the set of candidate keywords, a set of expected-content keywords which are determined to be representative of the previously sent content based on the inference detection; a receiving mechanism configured to determine whether outbound content is proper in response to receiving a piece of outbound content with another destination identifier, which involves performing one of; determining that the outbound content is associated with the first destination identifier, and the number of expected-content keywords present in the outbound content is below a first predetermined threshold; and determining that the outbound content is not associated with the first destination identifier, and the number of expected-content keywords present in the outbound content is above a second predetermined threshold; and a display mechanism configured to display the destination identifier for the outbound content and at least one expected-content keyword present in the outbound content, responsive to the outbound content being improper. 11. The computer system of claim 9 , wherein while determining the expected-content keywords from the search results, the query mechanism is configured to determine a term-frequency inverse-document-frequency (TF.IDF) weight for a respective word or phrase contained in a respective document.