What can ad agencies learn from startups regarding agile production? When should we deviate from the cult of agile? What are the barriers in the ad environment and legacy structure? How do you structure your teams?

This is such a good read. When I worked at small shops / startups (<20) agile made a lot of sense. It's harder to see in an agency our size. However, I love their system structure. For a PRODUCT it seems that tribes can be a bit myopic (Twitter, Google, and Facebook have similar structures as well). Agencies like R/GA are this specific. There's no "general" UX position there - there's specializations - mobile application, mobile web, product, and site experience. That pigeonhole structure - to me at least - leaves less room for flexible thinking.

Here's a rough sense of how I'd see it working at an agency our size. I can only associate this through the Target project lens.

Squad == Project / Campaign Team. This is pod-like, where people will rotate in and out based on demand. However the PO should be the same core leadership team.

PO == Project leaders. Ideally a trio of account, creative, and production. There every step of the way.

Tribe == The account you're working on (VW, Target, etc). The "scrum of scrums" seemed ideal. Like how Chris sends the weekly e-mail with the Target update. It'd be great to know what efforts have/have not been pushed with clients before.

Chapter == Similar titles. The Inventionists would be a cross-tribe chapter.

Guild == DEU LAN Tech team.

Good comparison. I think in many ways our teams are similar and our structure is malleable. What else is important? Beyond reporting structures and meetings, what are true differences?

I think the major difference is that (especially with the Spotify example - it might not apply to Google) is that they're working on a single product.

We have different clients, due dates, deliverables that are all over the place. We can promise an integrated experience - but it's practically comparing apples and oranges when it's a product experience versus a project-based experience.

Maybe that's too broad of strokes.

I also like this comparison:
blog.percolate.com