http://disclosurepolicy.org/ seeks to push an idea of transparency. Transparency in corporate sponsorship would plausibly make it easier for readers to detect skewed blogs.
Why is it important in blogging? Because advertisers are offering bloggers payment or gifts to create content about specific products or services, the blogger's interest in the product or service may be in part the financial gain. Whether the blogger would have included content in his/her blog about the product or service without gift or payment, the fact is the blogger is receiving payment for certain content.
They publish useful information for bloggers, advertiors and readers. They have a forum for discussion, and of course they have a blog.
You can generate a disclosure policy via a series of questions, presumably the disclosure policy will then be linked at the bottom of the page where all the other administrivia stuff goes.
I am a little frustrated because the questions do not fit the situation I have with the VisForVoltage forum. The Advertising and Content section of the questions has four choices none of which fit V's situation. VisForVoltage's target niche is very narrow and there are very few advertisers in this niche. Hence AdSense doesn't deliver a good choice of ads and there are few regular advertisers to draw from. I want to set up a direct sponsorship program for VisForVoltage and doing so would put the site outside the area of a third party ad service (e.g. AdSense). But they don't offer a choice where advertising doesn't influence content and it's not delivered via a third party service.
Be that as it may the questions do serve a useful form of disclosure including asking for employers, stock ownership, etc.