I dont think there is any theoretical limit for this. It uses more or less the same concept as differencing disks. Which from the referenced example can be quite nested.
I would however always try to keep the number of snapshots at zero. Using it only when strightly neccessary and definently never use it for production unless within a service window. In other words, I wouldnt let me machines run with a snapshot for a period past my service window.
Additional info on snapshots:
I have never seen an official statement on this.
In the end, the number of snapshots is not limited by Hyper-V, but by your storage and your configuration. Let me elaborate:
If you are using Hyper-V v1 and you have a default VM configuration - then your snapshots will be stored on the Parent parition system partition.
If you are using Hyper-V R2 and you have a dfault VM configuration - then your snapshots will be stored with the rest of the VM files.
If your VM is not running then a snapshot is only the addition of a differencing disk and an XML file. If the VM is running then a snapshost is the addition of a differencing disk plus a dump of the memory state of the VM (RAM) plus the XML file.
Brian Ehlert (hopefully you have found this useful)