The picture below is a common brick with a flushed mortar joint, which is very common to the original construction here in Capitol Hill.
The following picture is a concave mortar joint which is very common to typical construction in tract homes in modern construction outside of the city. This particular picture is in Capitol Hill, but at a newly-renovated and rebuilt area of masonry for a commercial condo building, NOT historic construction.
The following pictures shows a raked joint and a modern concave joint side-by-side.

The mortar joint on the left is a modern concave joint and a raked joint in the right hand side. As a side note, any joints between planar masonry surfaces such as shown here should be filled with an elastomeric or similiar flexible sealant.
The following diagram shows an assortment of different styles of mortar joints. Each is struck in a different style.
Click here to go to the list of all items on Capitol Hill Historic Masonry.