Well, I already knew about CVS, having worked in software configuration management for a decade now, but I too was blind to most aspects of DAE and encoding.
When I started lurking here, I was using WMP with an MP3 plug-in, and was seemingly happy with my 128kbps CBR MP3 files. In fact, MP3 was the only compressed encoding format I knew about. As far as I was concerned, MP3 meant "music on a PC"...there was no other way to do it. WAV meant "uncompressed" and I knew MP3 was "compressed". I never listened closely enough to hear artifacts, but mainly I dreamed of such elementary things as a way to make the volume the same across my music files and a way to get rid of those gaps between tracks.
Googling led me to Dibrom's audiocoding wiki, then to HA (and RareWares). The first thing I learned about here was LAME, then EAC, then MP3Gain, then foobar2000, then other encoding formats such as Ogg Vorbis, MPC and AAC.
With so much valuable (and verifiable) info, my supply of quality encoding-related tools went up dramatically, as did my demands. Now, I can hear a few artifacts in low bitrate files if I try hard, I insist on gapless playback and ReplayGain functionality...and being a control freak, I have a new, tightly defined method for extracting, encoding and managing my music.
HydrogenAudio has given me a new hobby/obsession, has brought me new friends, and has greatly improved my music listening experience.