We are currently doing some outreach to bloggers to review our products and provide us with backlinks (preferably followed). The bloggers get to keep the products (usually about $30 worth). According to Google's link schemes, this is a no-no. But my question is, how would Google ever know if the blogger was paid or given freebies for their content?
This is the "best" article I could find related to the subject: http://searchenginewatch.com/article/2332787/Matt-Cutts-Shares-4-Ways-Google-Evaluates-Paid-Links
The article tells us what qualifies as a paid link, but it doesn't tell us how Google identifies if links were paid or not. It also says that "loans" or okay, but "gifts" are not. How would Google know the difference? For all Google knows (maybe everything?), the blogger returned the products to us after reviewing them.
Does anyone have any ideas on this? Maybe Google watches over terms like, "this is a sponsored post" or "materials provided by 'x'". Even so, I hope that wouldn't be enough to warrant a penalty.