The standard provides a general way to represent activities. For instance, the sentence "Jack added Hawaii to his list of places to visit" would be represented in ActivityStreams as actor:jack, verb:add, object:Hawaii, target:placestovisit.
The largest open source library (based on watchers) is Stream Framework, the authors of Stream Framework also run getstream.io. In addition there is a trend of SOA (service-oriented architecture) where third parties power this type of functionality. [citation needed]
{
"@context": "https://www.w3.org/ns/activitystreams",
"summary": "A note",
"type": "Note",
"content": "My dog has fleas."
}