I did not realize it at the time but my recent PSK-31 contact with SV1BDO/3 in Egio, Greece is now my record longest distance two-way communication via amateur radio. The distance between our antennas: 5,213 miles. Amazing!
The image above is an e-qsl (electronic qsl). Traditionally amateur and commercial stations have issued QSL cards to verify contacts and reception reports. Up until recent times QSL cards have always been printed on card stock like a postcard. Exchanging paper QSL cards is still practiced among amateurs and some short wave broadcasters although the e-qsl digital confirmations are gaining acceptance due to many factors. The always rising cost of postage and the long wait on international snail mail are probably the greatest.