it's just water, normal for exhaust to do that.
i've also noticed that cars that have been sitting for a long time tend to have more condensation out the tailpipe than a car thats only been sitting for a day or so.
-2000 3.8L TKO600, 1.8 60ft, 8.71 @ 81mph
-1988 Jeep XJ, bone stock 2wd
-1994 Jeep XJ 4wd, 3" lift, 31" tires.. rust in peace..
-1997 Jeep XJ 4wd, 7" lift, 35" tires, front/rear lockers
-Bronze Level Porsche Technician