Stockholm is an archipelago. Central Stockholm is comprised of 14 islands, while many more make up the greater metropolitan area. As an urban structure, this produces many interesting conceptual and physical parallels both to other cities and how we imagine the experience of the city to be. While Venice and other canal cities could be described in similar terms, i think with stockholm the scale of the city and of the waterways changes the effect. While Venice is a city carved through with narrow canals, its base condition is solid ground and architecture. Stockholm is very much a collection of separate islands within a watery landscape. The figure/ground relationship is reversed, and combined with the larger scale of Stockholm's islands (as opposed to Venice's aquatically defined blocks) Stockholm begins to accrue a series of identities, not unlike OM Ungers' proposed plan for consolidating Berlin into an urban archipelago: a series of consolidated urban islands on an open field.
I would love to see Stockholm 100 years from now, when the forces of preservation and development have pushed the city to even further physical extremes than already exist. Each island would be driven by a different zoning requirement (historic, commercial, residential, etc.) that would lead to an incredibly heterogeneous city.
The transportation network below Stockholm is a fitting counterpoint that ties together the city's islands, serving as a total 'other' in relation to the city above. Raw, hewn stone surfaces, archeological remains, and massive art murals define the Stockholm subway. It is space, without engaging the norms and label of Architecture.
Stockholm's organization interestingly parallels Guy Debord's 1957 psycho-geographical map of Paris as a set of disparate places abstractly linked by the metro. I imagine that 100 years from now, as the physical archipelago of Stockholm becomes increasingly diverse and each island's identity further concentrated and intensified, the physical and pscyhological geographies of Stockholm as Debord would map it will converge to produce a city that is truly an archipelago in both senses.