proposal for new classes Activity and Action

Hello,

The three of us (Will, Jason, and I) have an idea for improving schema.org's
representation of activities, and we'd like to start a discussion about the
merits of our proposal. We've tried to adopt some of the core insights of
ActivityStreams while remaining compatible with the (many) "implied
activities" that can be drawn from schema.org items in general.

The proposal may be found at
https://docs.google.com/document/d/1VYZ9FmN7Vl2PzzR1kX3KZgfdPK-qUfxR3z12NC3i5V0/edit.
Comments are turned off on the document so the discussion will be on
this
list.

>From the top of the document:
"""
Historically (in earlier schema.org versions), the
http://schema.org/UserInteraction type was focused on reporting aggregate
interaction counts, despite being a subclass of Event. Over time it has
shifted more to representing individual interactions. This transition has
not been smooth; the original intent is still reflected in Example 1 for
UserInteraction, which uses subtype names as part of a structured text
interactionCount. It is also reflected in the names of the UserInteraction
subtypes, which are plural, as well as the duplication between Comment/text
and UserComments/commentText. UserInteraction subclasses UserComments,
UserCheckins, and UserTweets, when interpreted as individual interactions,
contain creative content that would benefit from many of the properties of
CreativeWork. Other subtypes of CreativeWork, such as Review, lack
corresponding subtypes of UserInteraction. AggregateRating has its own
type, while other types lack corresponding types to represent aggregates.

To resolve this tension, this proposal:

   - creates a new type, Activity, to represent a single activity, with
   consistent properties (across all activity instances) to structure the
   grammar of the activity;
   - creates a new type, Action, with subtypes that describe classes of
   “verbs” within the grammar;
   - creates a new type, AggregateActivity, to represent an aggregation of
   activities e.g. in CreativeWork/interactionCount;
   - adds a new property Thing/action to indicate an action that may be
   performed on a thing; and
   - deprecates UserInteraction and its subclasses, and AggregateRating, in
   favor of the new types.

"""

Looking forward to your thoughts,
d