Direct Marketing
Direct marketing offers a capability that advertising cannnot deliver - the ability to address an individual with an offer, and then to track the response. Advertising is far more shotggun in approach, and so its effectivness if far more difficult to measure or tweak.
While advertising lacks an accurate way of measuring the effectiveness of adspend, direct marketing offers the ability to track each and every marketing campaign. Testing and tracking is key component of direct marketing. As such, no campaign can be considered a failure if the campaign data is analysed - as the marketing team learns how not to market a particular product or service. Advertising offers no such direct feedback mechanism, and so is far more hit and miss in terms of determining how to tweak, or whether to totally revise a marketing campaign.