MCO - Orlando International Airport
MGM - Disney-MGM Studios
MK - Magic Kingdom
MNSSHP - Mickey's Not So Scary Holloween Party
MJJP - Mickey's Jammin' Jungle Parade
MS - Main Street
M:S - Mission: Space
MSEP - Main Street Electrical Parade
MV3D - Jim Henson's Muppet*Vision X3D 4D
MVMCP - Mickey's Very Merry Christmas Party
MYW - Magic Your Way

NoJ - Night of JoyOKW - Disney's Old Key West Vacation Club Resort
OPR - Old Port Royale (at Disney's Caribbean Beach Resort)
OUaT - Once Upon a Toy Store (Marketplace)

PAP - Premium Annual Pass
PH - Planet Hollywood (part of Downtown Disney)
PHP - Park Hopper Pass
PI - Pleasure Island (part of Downtown Disney)
PIAP - Pleasure Island Annual Pass
POFQ - Port Orleans French Quarter
POR - Disney's Port Orleans Riverside Resort
PoC - Pirates of the Caribbean
PotC - Pirates of the Caribbean
PS - Priority Seating
PSA - Priority Seating Arrangment
PW - Primeval Whirl

R&C - Rose and Crown Pub in Epcot
RC - River Country
RFC - Rainforest Cafe

SB - Stormalong Bay (the main pool at the Yacht and Beach Club)
SDCT - Share a Dream Come True Parade
SE - Spaceship Earth
SGE - Stitch's Great Escape!
SM - Splash Mountain
SM - Space Mountain
SMC - Stars and Motor Cars Parade
SOG - Shades of Green Resort
SplM - Splash Mountain
SSR - Saratoga Springs Resort
ST - Star Tours

TDL - Toyko Disneyland
TDS - The Disney Store
TL - Typhoon Lagoon
TLS - The Living Seas
TM - Big Thunder Mountain Railroad
TMK - The Magic Kingdom
ToT - The Twilight Zone Tower of Terror
TS - Table Service Meal
TSI - Tom Sawyer Island
TK - TimeKeeper
TT - Test Track
TTA - Tomorrowland Transit Authority
TTBAB - Tough to be a Bug
TTC - Transportation and Ticket Center

UoE - Universe of Energy
UHP - Ultimate Hopper Pass

V&A - Victoria and Albert's
VB - Disney Vacation Club Vero Beach Resort
VM - Disney Village Marketplace (now part of Downtown Disney)
VMCP - Mickey's Very Merry Christmas Party
VotLM - Voyage of the Little Mermaid

WDW - Walt Disney World Resort
WHS - Wildhorse Saloon
WoD - World of Disney Store
WL - Wilderness Lodge Resort
WLV - Wilderness Lodge Villas
WoL - Wonders of Life
WoM - World of Motion
WS - World Showcase (@ Epcot)
WS - West Side (now part of Downtown Disney)
WWoS - Disney's Wide World of Sports

Y&BC - Yacht Club Resort and Beach Club Resort
YC - Yacht Club Resort
YoMD - Year of a Million Dreams

Some frequently used non-Disney abbreviations:

:) smile
;) wink
:( frown
:'( = crying
>:-} is a devil
0:-) is an angel
{ } = hug
:* = kiss
:X = my lips are sealed
:P = sticking out tongue
{:-*} Hugs and Kisses
@--->--- A Rose
LOL = Laughing Out Loud
ROTF = Rolling On The Floor (laughing)
BTW = By The Way
RSN = Real Soon Now
IMHO = In My Humble Opinion
IMNSHO = In My Not So Humble Opinion
GMTA = Great Minds Think Alike
F2F = Face-to-Face
TTFN = Ta Ta For Now
AFK = Away From Keyboard/Keys
BRB = Be Right Back
ROFLWTIME = Rolling On Floor With Tears In My Eyes
WTG = Way To Go

BIL = Brother in law
DD = Dear Daughter
DH = Dear Husband
DS = Dear Son
DW = Dear Wife
FIL = Father in law
MIL = Mother in law
SIL = Sister in law