This was posted originally in the Millennial Media tech blog . The longer products are used before end-of-life, the higher the return on investment. Therefore, we plan our products to be robust enough to withstand market changes and technology evolution. However, in the ever-evolving area of campaign optimization at Millennial Media we build features to be used, learned from, and replaced quickly. Therefore, when we replace a feature, it’s more likely to be because of the feature’s success than due to an inadequacy. Quick end-of-life means that the feature was widely adopted and that we gained meaningful insights from its use, enough to justify investing in the next feature iteration. Paraphrasing Porras’ and Collin’s famous business book, we “build not to last”. Here’s a typical example of how it may occur: Our data-science team comes up with an algorithm to partially automate a certain optimization process. Next, we build an interface to easily initiate, monitor and con...