In the comments of Matt Mullenweg's announcement for the WooThemes acquisition, someone asked if he could bring back WooThemes' affiliate program.
I was pretty surprised by his answer:
I think it didn’t work for them well the last time around, but definitely something [we] could reconsider in the future once things settle down. Automattic is considering an affiliate program for our other services right now too.
I'll keep my ear close to the ground on this one. I'm not sure what an affiliate program would look like for Automattic, but it'd pretty interesting to see how they implement it. I bet some folks could do quite well as affiliates for Automattic's services (think the variety of WordPress.com upsells, or VaultPress subscriptions).