What is the purpose of PD?

This week I led a session at the Coding in the Classroom Summit.  The session was titled.  "So you've got data. Now What?!".  If there is one thing I have learned about session titles, they need to have a "Click Bait" type of name.  But essentially the session was about looking at the data side of computer science.  I ended up doing a "Teacher-Learner-Observer" type of session which featured one of code.org's Computer Science Discoveries lessons.

That's not really the most important part of this post or what motivated me to think-out-loud-via-blog.  Really what interested me was the fact that the session went exactly as I had hoped it would, BUT I am not sure if it was what the audience wanted.  I am not sure if the audience would have considered it a "success".

Code.org has totally got me drinking the kool-aid of using the "Teacher Learner Observer" model to create meaningful PD experiences for teachers.  However, at this conference, many of the sessions felt a bit like an information dump.  I suppose there is a time and a place for an information dump, and I usually get my information from Twitter or other blogs/social media - if we are meeting in person, I don't really want a list of all the things you do.  I mean, I want that list, but written down, as a one pager, I don't want you to read it to me.  I am going to google everything on that list later any way.

This made me think about what teachers expect to get out of PD. Each format is a bit different, what you expect to get at a keynote.  Dan Meyer also has a great post about how he presents.

Here are my ideas about how I want to run my PD:

1. I want it to tell a story.  People like stories.  Stories can captivate.  I want my story to have a beginning, middle, and end.  Just like all stories, I want the middle to be the bulk of the story.
2. I want attendees to have an experience.  Just like how I strive to teach math and how I teach CS, I want attendees to remember the experience of participating in something meaningful.  I want them to have an "a-ha".   
3. I want the PD to be either be immediately applicable or be a hook for some big idea.  I want people to leave thinking that what they just experienced will be useful to them in some way.  It might be something they can do tomorrow in their classrooms or maybe a summer research project that they do. 

These are just initial ideas of mine but I wonder what other teachers think of as successful PD?  What is the best PD you have ever attended and what made it that way?