This would be fantastically niche and tech-person-oriented, probably not the right move for the company as a whole. That said, nothing stops you from writing a bot on top of Twitter to power any of these interactions.
It would be a big niche if you consider how many people use Excel functions. It could make Twitter part of enterprise and group communications infrastructures.
@friends Don't forget my birthday party on #(Aug 20, 8pm) at #SomePub
or
@friends Don't forget my birthday party! #invitation(Aug 20, 8pm, SomePub)
And I want to be able to create a list where all invitations from people in the @friends group go
And finance people could do things like
Twitter has bottomed #buy(TWTR)
And I want to be able to specify a rule that makes these messages go to my stock trading list