Other posters got it right. "Compact geometry" as it applies to frames, means that the top-tube is higher at the front than at the seat tube. This slant means that stand-over height is mostly removed from the bike fit equation. The importance of this is that the cyclist can then buy the frame based on the IMPORTANT measurement - the distance between the seat and the handlebars.

For some riders (particularly those with short legs and long torsos), the "conventional geometry" with the top tube parallel to the ground just doesn't work. Why? Because if the bike is purchased in a size that allows the rider to safely stand-over the top tube with clearance for the privates, then the top-tube is too short. Compact geometry alleviates this problem.

The Specialized that you mention is a great bike. If it fits you, you shouldn't care if it has compact geometry or not. The frame geometry isn't what is important. How the bike fits you is.