'skinny strings' means a modern hmpe fiber string (dyneema, vectran, spectra, etc - dynaflight, ts1, 450+, fast flight, etc.) with a much lowered strand count. for bows up to 50# or so, 6 strands is a safe bet, and 8 strands for 50# and above.
dacron skinny strings are stretching it way too far, pun intended.
low strand count strings are lighter and less prone to making vibration noises on arrow release. some folks also note increased arrow speeds.
any one of trad gang's string making sponsors can hook you up with a superb skinny string for you to trial out for yerself.