Based on this post from Zoho CRM, it appears that LinkedIn has cut its CRM partners to just two - Salesforce and Microsoft. And, if you visit the LinkedIn Developer page, it becomes clear that they have chosen to work with just those two partners.
In an environment where APIs and web services are at the core of innovative web applications, LinkedIn is taking a step backwards towards a walled garden. From a financial standpoint, I understand it. LinkedIn has an incredibly unique and valuable database. And SalesForce and Microsoft not only have the huge installed base, but also the deep pockets to make this a hugely profitable partnership.
The exclusivity may make sense from a short-term revenue standpoint, but it's certainly not providing value to many of its users. I don't know the terms of LinkedIn partnership deals, but hopefully they can come up with an access plan that could make sense for some of the smaller, upstart providers like Zoho, Nutshell and others.