When vertices and/or edges are selected, Connect Components connects them via edges. Vertices are connected directly to connecting edges, while edges are connected at their midpoint.
Note: You can access Connect Components from the marking menu by clicking 
+ 
when the polygon is in Edge, Face, Vertex or Vertex Face mode.
+ when the polygon is in Edge, Face, Vertex or Vertex Face mode. Edit Mesh > Connect Components > 
- Insert with edge flow
-
Lets you insert connecting edges that respect the curvature of the surrounding mesh. This option is disabled by default.
- Adjust edge flow
-
Enter a value or adjust the slider to change the shape of the edges before they are inserted
Set Adjust Edge Flow to 1 to transform the surface curvature of the edges to respect the curvature of the surrounding mesh. At 0 the edges move to the middle of the other nearby edges, creating a flat surface.