There's a heated debate in Markus Voelter's blog on the relationship of OSGi to Service Oriented Architecture (SOA). I must confess to having thought of OSGi as an example of a SOA until now.
One of the big benefits of SOA is a standardised way of lashing together myriad legacy (and new) systems. You may have seen the 'circuit diagrams' some organisations draw to illustrate the problems they face.
Wikipedia discusses SOA and quotes an OASIS definition:
A paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. It provides a uniform means to offer, discover, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations.
While OSGi can provide a very useful single process component model, it doesn't directly address distributed systems. Perhaps Markus should add 'distributed' to his list of SOA attributes.