Interesting numbers we have collected around Community ROI. Please feel free to add your own:
Source: McKinsey - Community members by 5x more & 2x as often than non community member
Source: eBay - Members spend 54% more than non-members
Source McKinsey - Members visit your site 9x as often and view 4x as many pages per visit vs. non-members
Source (Jive Customer) - Company had 8,569 discussions around the core product and 119,059 discussions around specific events
I find ROI hard to measure. I think we, as a company, see our Community as a free value-added tool, rather than a driver of revenue. In my own setup, I think the only ROI we can really measure are leads created from our Community - which isn't that easy either. There are occasionally opportunities for "insude selling", i.e. selling extra training, consultancy, upgrades, etc to existing customers.
Context: we're a smallish software firm in the UK with a global customer base.
Keep the interesting articles coming!