For Hagel, inside-out architectures are those that have evolved in many large organizations over the past couple of decades: starting from centralized IT architectures, gradually embracing distributed computing (client-server) and SOA, and very cautiously moving towards B2B. Such architectures are generally transactional, and controlled ("held captive" says Hagel) by IT architects.
A key challenge for inside-out architectures is the ability to connect and coordinate activities across large numbers of independent business partners, and to scale up to large and highly complex service-based ecosystems. Hagel believes that outside-in architectures will provide better support for complex collaborative ecosystems. He calls this relational - not using this term in the traditional IT sense ("relational databases"), but focused on supporting business relationships (and long-term business transactions) rather than short-term transactions.
The term "outside-in" seems to have a range of overlapping meanings, including:
- Looking at your business from the customer's perspective. There are several consultancies that claim to offer this as a service. For example, here's a curious page on the Outside-In company - with painfully bad graphic design and a revealing spelling mistake ("ourside in"). See also High-Yield Methods.
- Business-driven systems. For example, Zapthink uses the term to refer to "flexible business processes that respond to the way humans work, rather than processes that constrain humans to work the way the systems want them to work".
- Strategic Outsourcing. See for example What India and China can teach us about Innovation by Hagel and Seely-Brown.
- Outside-in SOA. This term seems to have been coined by Dave Linthicum, and refers mainly to interaction with external services (SaaS). See also Chuck Allen.
- Some of them are largely about extending the scope of the solution - finding new (more cost-efficient, more flexible) ways of satisfying the same old requirements. I think strategic outsourcing and SaaS come under this heading.
- Some of them are about extending the scope and perspective of the requirements - trying to add value to the customer's process, not just your own internal processes.
- And some of them hint at the need to reframe architecture itself - looking at the positive space between systems and organizations, not just the systems themselves.