Wide v. Deep is an endearing blog post by a programmer repeatedly promoted from the trenches into management against his will. He gave an honest go of it, but ultimately found he was a programmer at heart and needed to dive deep on few things at once, whereas a management role kept demanding he stay at the surface to work shallow across many projects.
To explain the difference between a manager's and a programmer's workload, he created these two diagrams:
We've always looked for people for our team who can operate in both mindsets. They need a strong vertical skill to dive deep in some area the rest of our team can only wade in, but they also need the passion and the mind to imagine and solve problems outside of their comfort zone. We often call this a 'generalist-specialist.' Overlap these diagrams and you see something like IDEO's concept of the "t-shaped person":
The benefit is getting imaginative problem solving from someone capable of rolling up their sleeves and actually doing something about it. T-shaped people don't observe from the sidelines and do reports, they design solutions.
In practice there are only so many of these Renaissance people to go around. You wouldn't necessarily want or need to staff your entire team with nothing but generalist-specialists--it's also possible to get the t-shape from the team itself.
Take 37signals' idea of the Three Musketeers for launching your web app: "Start with a developer, a designer, and a sweeper (someone who can roam between both worlds.)" Together they crossover and compliment each other's problem solving skills and get something done end to end.
Or consider how Peter Merholz's describes a mix of "T- and I- and bar-shaped people, and I suspect that the strongest teams are comprised of all three that work in concert." What would this sort of team look like?
A T-shaped Team
The bar-shaped person may not necessarily be a manager, but someone owning the customer touch points in the visual design or copywriting across your site or application. They work in a broad fashion to help the experience feel like it has direction, vision and personality.
The "sweeper" is your classic t-shaped person. In development we find it incredibly helpful to have a team member capable of speaking and working in both the language of the deep dive, I-shaped developer and the bar-shaped designer-writer-manager. They help translate and cross-polinate ideas. They get thought turned into execution faster.
Maybe if the author of Wide v. Deep had more generalist-specialists to work with, he wouldn't struggle with the stark divide between management and development. He might find the ability to influence across projects in between those deep dives into code.