Ask HN: What kind of data do you share from business to business?

If you reduced your b2b exchanges to the simplest schema, what would they look like? For example a response to a bid could look like this:

``` {

  item_id: int

  bid: int // USD

  size: enum // { S, M, L, XL }

} ```

Emphasis on the word "data", as in not your natural language communications, unless there's the possibility to describe them in such a structured way.