I presume "secular usage and technology trends" means "is its growth down to the fact it happens to be down to the market it plays showing strong growth trends even without hype and marketing spend associated with this particular company". Can only assume the secular trend he's thinking of there is growth in "business prospecting tools" which is the potential area for Microsoft to build revenue generating services that also integrate with their CRM and Office, and not the established and plateau-ing LinkedIn userbase, which is simply a potential strategic advantage for Microsoft products in that space.

Sure, Microsoft don't have a great record with their acquisitions, but the opportunity for them to generate more revenue directly and indirectly from this is huge.