After trying for about a year, I finally collected all of the QSL cards required for Worked All Continents (Mixed) sponsored by the International Amateur Radio Union (IARU). You achieve this by making radio contacts with the six continents (the islands in the Pacific count as Oceana/Antarctica). I actually got the last continent back in May, but I was under the impression WAC could only be earned with QSL cards - so I started sending off for cards I was missing (namely Asia and Africa). After the last one came, I mailed them all off to the ARRL and they sent me the certificate:
I don't regret going after the QSL cards, but it was not necessary. Logbook of the World (LoTW) credit is accepted, it just isn't a straightforward process - there is no way to directly apply for WAC in LoTW. You have to apply for DXCC, select the 6 QSLs you want to submit and pay for them to be applied to your DXCC record. Then you fill out the WAC application and pay that fee separately. Current instructions are located here: http://www.arrl.org/files/file/DXCC/WAC and lotww_pdf_20141.pdf
Doesn't make sense? Yea, I'm with you, especially if you read the WAC application form it makes it sound like it can't be done. Also, "Hybrid DXCC" (combining QSL cards and LoTW credits) works exactly the same way.
If you know a little German, or are handy with Google Translate (some pages are in English if you press the British flag, but I've found it to be a mixed bag), DARC (Deutscher Amateur Radio Club - the equivalent of the ARRL in Germany) will also give you credit for LoTW and e-QSL.cc QSLs toward WAC. They don't send you the paper version like ARRL, they send you a PDF- but it doesn't cost anything.
I applied for the Digital and 40 Meters endorsements for this one. It only took a couple days for them to process. DARC has other cool German awards worth looking at and setting up on their online QSL system (the DARC Community Logbook):
However, I definitely enjoyed getting QSL cards from all the different countries. I definitely don't want to do it for DXCC, but I have much respect now for all the hams that got DXCC with only cards.