Towards Whitehat Content Farms?
Defining A Content Garden

When Is A Content Farm Not A Content Farm But A Garden?

Given Google's new announcement about its plan to root out content farms, is there ever a place for creating a website that aggregates content, or encourages people to submit content in return for just a commission or the honor of contributing content?

I think there is and those white hat content farms are actually gardens of content, where content gardeners, editors tend the garden to remove weeds, and curate the best content in one place or point to the best content on the web. aggregates content by an editor writing a unique synopsis of the article. Because of the synopsis there's no duplication of content, while columnists submit unique content. However, no unique articles from paid journalists are written, thereby reducing the costs of content creation, because it’s either free from columnists or aggregated from the web. Instead pays an editor to curate content from the web, and encourage submissions from influential authors on marketing.

Mashable pays its journalists, but also encourages columnists’ submissions that are free, in the process, lowering costs for content acquisition, and increasing the number of links to their site from influential writers who want to promote a published article on Mashable. The site spends money on writers, but also editors and community managers who encourage participation.
ZDNet has paid content, and content from columnists that's free; some of the columnist posts are republished from original websites like Forrester Research. ZDNet gains low cost high quality content, and links from the contributors. 

The list goes on, I believe the web has changed from just a few years ago, content farms may be spam, but building a content garden like Mashable, ZDNet, or Social Media Today make sense if you want to compete.