It is said that the Vertex and Anti-Vertex work as the other angles in the chart. Any planet or point tightly aspecting or, more importantly, conjunct the Vertex assumes special importance on the chart and the life of the native.
The Vertex has to do with fate, like the Lunar Nodes, but differently from the latter it focuses primarily on fateful meetings or relationships. The reason for that seems to be that it always falls between houses 4 and 9, which concern others.
I have done little research on the practical nature of the Vertex/Anti-Vertex axis but it's commonly accepted that important people on the life of the native will more than likely have some planet conjunct or tightly aspecting his/her Vertex, as with the Nodes. Also, when two people meet by fate, either one of them will have a progressed planet conjunct the other's Vertex or their current Solar or Lunar return (usually both) will show important points conjunct the axis. The timing of these fated encounters always seems to be very precise and they are mostly beyond control.