When being asked to serve in an advisory role where you are not being compensated and will not have authority (I.e. Like a board member) you still should ask some fundamental questions. You are in effect exposing your credibility to how this business operates in the market and how market sentiment will impact you.

You want to identify some sense of financial health (you would be getting this by default if you were being compensated as an advisor)

I would suggest speaking to a board member will be beneficial

I would also do some homework to establish your own sentiment on this company if they have any public visibility (including searching for their team members on social networks)

Also ask:

- who are competitors
- how do you differentiate and head off roadblocks set by more established competitors
- what is your position in funding and when do you need additional rounds (impacts how your recommendations can be put to use in realistic fashion)
- who are you trying to reach, both influencers and prospective customers

This should give you a beginning picture of the company and help you decide if you can really help.

I've both recruited advisory boards and served on those boards as well as serving as a board member.

I'd be glad to dive into specific due diligence or other factors if you have more specifics about your possible participation. Glad to hold a brief call to discuss.

Definitely start with those who have successfully built up a business that has led to revenue & stability. These would include:

37 Signals - http://37signals.com/svn (a really nice balance of tech, operations and effective best practices for running a business you want to work at)

Buffer - http://blog.bufferapp.com - a strong example of transparency and letting your audience get to know you

Reviews are a powerful capability that gives credibility for transparency. You also have to be prepared for those open conversations - as you know from referencing those three sites. This means committing to authenticity (as cooked reviews are a major mistake some have attempted) and navigating the appropriate moderation of reviews.

It really is driven by what your B2B goals are on your business site. Some sites have handled building credibility through questions and answers (i.e. Quora, LinkedIn, et al). There you can allow users to rate answers - and also allow for flagging of those that don't pass the genuine test.

I call it the Amazon effect (others use eBay) as they were among the first to offer reviews on a massive scale. It is powerful and influences decision making, purchasing and attitude toward products, services or even the site itself.

Having designed policies for social communications, customer service communications and more in B2B environments - I've seen reviews work well and not so well. It can be done - but requires judicious planning for rules of moderation and engagement, and for how readers of reviews can reward or flag them.

I'd be glad to hold a follow up on this and talk through those elements.