Never mind tablets, smartphones, and mobile-social-location-photo-sharing apps. Heck, never mind computers . The single most important technology of the last half-century, the one that has drastically changed the day-to-day existence of very nearly everyone on Earth, remains the plain old GSM phone; unloved and half-forgotten in NYC and Silicon Valley, but still used by the billion in the rest of the world. That's why Boston-based TxtEagle last week raised $8.5 million from a consortium including Spark Capital and RBC Venture Partners. Well, that plus a clever business model, a nifty technology platform, and partnerships with 220 mobile operators in 100 countries who between them cover 2.1 billion subscribers. TxtEagle offers crowdsourcing and market research in developing markets. Clients such as UN researchers or advertisers hire them to survey masses of people; TxtEagle then forwards the survey (or other task) to thousands of individual members via their GSM phones, and pays them upon completion. You might guess that they communicate via SMS, and pay with cash — but no.