At the most basic level FLARM is transmitting GPS data and looking at other FLARM units GPS data.... the antennas are not directional etc. It's all about software and focus on the glider community and making the traffic warnings usable/reducing false positives and providing the NMEA based data integration with glider traffic displays and glider flight computers... nothing those other systems can do. (...)

Thank you for taking your time to clarify it to me. You are right, I have not flown in a FLARM equipped glider yet. But I find this your statement very important and revealing to me: "It's all about software and focus on the glider community". So the questions that bothers me all the time is: with the ADS-B becoming so common and mandatory for most aircraft, why should I have two transmitting systems on board (FLARM and a transponder - think about price and power usage). If it's all about software, why can't we have software using the ADS-B transmission (more universal, stronger ergo better visible) to provide us, glider pilots, with the information (visual/acoustic) equal to that produced by FLARM.

Let me make it clear: I am for the safety, visibility, awareness etc. I have a Microair Mode C Transponder and the ATD-300 Traffic Watch working beautifully, and I know it's not enough. I'm not against the idea behind FLARM and I bow down before the guys who invented and implemented it - but now it's the NextGen and ADS-B era - let's adapt to it! If a FLARM device appears on the market with the added ADS-B-Out feature, I'll be among the first to order, ready to invest in it whatever is necessary and justified.