An excellent post over on SaaS blogs locks at two possibilities for PaaS. One is very vertical in nature (AppEngine, Force etc) providing all the various layers needed for the offering (library layer, delivery layer, compute layer). The other is much more horizontal in nature where, say, a vendor provides the compute layer but do so very broadly.
Sinclair contends that the latter, more decoupled topology is favourable in that it minimises the risks involved in breaking out one sub-optimally performing layer.
Conceptually speaking there would seem to be something to be gained from going with the vertical topoloy, mnimising relationships, points of contact building efficiencies. I also however understand Sinclairs concerns about the risk of a monolith.
Interesting discussion
Ben Kepes is an analyst, an entrepreneur, a commentator and a business adviser. His business interests include a diverse range of industries from manufacturing to property to technology. As a technology commentator he has a broad presence both in the traditional media and extensively online. Ben covers the convergance of technology, mobile, ubiquity and agility, all enabled by the Cloud. His areas of interest extend to enterprise software, software integration, financial/accounting software, platforms and infrastructure as well as articulating technology simply for everyday users. 