Buffer Overflow. We are bombed with more data than ever before in the history of mankind. Unfortunately, this information overload is accompanied by an unnecessary waste of energy and increasing emissions of greenhouse gases. Data is electricity and electricity means CO2 emissions. Technical progress all too often results in unexpected rebound effects. The greed for data and its inflationary output has not only ecological consequences, but also implications concerning our privacy. The keyword here is Big Data. This talk provides a way of thinking about making our frontends more sustainable, leaner, fairer, more accessible, more understandable, and therefore also more performant— sometimes only with a well-founded "NO"! The talk will give an insight into practical process strategies and tools that make it possible to achieve a doubly sustainable improvement in the user experience, frontend code, performance, and privacy of our websites.