It's axiomatic that in software of any complexity, the ecosystem of plug-in products, tools, compatible APIs, and developer community can become \n\nreally important. In certain software product categories, the importance of the ecosystem can swamp any feature advantage that an upstart product \n\nmay have, leading to what economists call a natural monopoly. This doesn't apply to all product categories, though. And in very mature technologies, it is possible to unseat the established leader's ecosystem \n\nwith a "good enough" substitute. Think "The Innovator's Dilemma," and then think Linux, Open Source, and Google docs.But if you look at cloud computing, there's no part of it that could be called "very mature." The argument can be made that the cloud is all based \n\non Web services, so the ecosystem doesn't matter as much as it did with traditional software. But that argument is na\u00efve, at best: at the detail \n\nlevel, cloud vendors' APIs are proprietary, and learning curves can be quite steep. And that ain't gonna change. So the number of tools, plug-ins, and developers can really matter when evaluating cloud vendors. Where in the clouds is the ecosystem critically \n\nimportant? The general characteristics of these segments are:\n\n\u2022 Technical platforms, such as integration, logging, development, or deployment \n\u2022 Social Networking platforms -- the usual suspects\n\u2022 Advertising and gaming networks -- the usual suspects\n\u2022 Commerce platforms, such as Amazon, eBay, or PayPal\n\u2022 Services that are toolkits disguised as applications, such as Google or Salesforce.com\n\nFor cloud vendors that span two or more of these characteristics, there's a doubling of the ecosystem's impact. The valuation of Facebook and \n\nLinkedIn doesn't come just from the number of eyeballs. At the other end of the spectrum, there are lots of cloud services where the ecosystem isn't critically important, such as e-mail, storage, news \n\nfeeds, or photo sharing. And certain kinds of cloud apps such as invoicing, banking, or HR can get away with just a couple of connectors to popular \n\naccounting packages.Measuring the Size and Quality of the EcosystemIn any vendor competition, there's the stuff that counts and there's noise. The same goes with the ecosystem. For example, Microsoft can \n\nprobably claim the most APIs of any vendor, the largest developer community, the most plug-in products, and the most consultants. But almost none \n\nof that applies to the cloud at this point, and nobody thinks they have the strongest cloud ecosystem.So the first part of measuring the strength of the vendor's ecosystem is clearing away all the obvious marketing chaff. Next step is to look only \n\nat the part of the ecosystem that's relevant to the cloud service you will actually be using. What remains still needs to be vetted, as there will plenty \n\nof obsolete or uninteresting "information" about the ecosystem. For example, you may find 100 vendors who are nominally partners, but if only 20 of \n\nthem are in your country and you've never heard of them before, some additional scrutiny is warranted. Likewise, you may find lots of partner \n\nproducts and services that may not have been updated in a long time. A strong ecosystem has vendors who have not only been there a while, but \n\nhave released several versions of their products or services. If the ecosystem has a vendor ranking and rating system (Salesforce.com's \n\nAppExchange is a great example of this), look for the quality and recency of customer feedback. The two major axes for measuring the ecosystem are products and people. In my experience, the number of people committed to the \n\necosystem is more important in the long run than the product. If there is plenty of demand and a good supply of practitioners, the plug-in and add-\n\non products will be forthcoming.Handicapping the Early ScrambleIt can be tricky to evaluate cloud vendors when the category is in its early days and there is no clear winner, either in features or ecosystem. If \n\nthe cloud category you're looking at is strongly impacted by ecosystem effects listed above, you need to gauge:\n\n\u2022 Current size and growth rate of developer community\n\u2022 Relative happiness of the developer community (as indicated by posts into the community forums, number of job\/consulting openings, etc.)\n\n\n\u2022 Size and growth of the number of plug-in products or services\n\u2022 Number, quality, and profitability of vendors participating in the ecosystem\n\u2022 Number, scope, quality, and documentation of relevant APIs\n\u2022 The cloud vendor's investment in the quality of the platform and the growth of the ecosystem\n\u2022 Number of staff the cloud vendor has dedicated to that growth\n\nThis might seem like you're a Wall Street analyst trying to predict the future. And in a way, you are\u2014so it won't hurt for you to see if any of \n\nthem has opined on the vitality of the cloud vendors in the category you're working with. David Taber is the author of the new Prentice Hall book, "Salesforce.com Secrets of \n\nSuccess" and is the CEO of SalesLogistix, a certified Salesforce.com consultancy \n\nfocused on business process improvement through use of CRM systems. SalesLogistix clients are in North America, Europe, Israel, and India, and \n\nDavid has over 25 years experience in high tech, including 10 years at the VP level or above.Follow everything from CIO.com on Twitter @CIOonline.