what kind of tag systyem is this
 

http://www.djdavidmorales.com/home/event-tag-help

how does this tag system work what type of script or code you need to do something like this ?

hahahahhaah

The tag system is built on the links from the back off all the sites the information is pulled from, I would guess through api's, to code this would depend on how good the skills of the coder were and also how good the api was and the request rules it has in place as large scale sites built on this might need to pay due to the number of requests which would be submitted (Some sites charge, some don't).