Recommendations and reviews are common in the consumer world, where customers routinely yelp, buzz and epine about everything from air conditioners to yard ornaments. Search for any local restaurant, retailer or other establishment and customer reviews are almost certain to be featured prominently in the results. Online shopping sites host reviews of products and sellers, and Angie’s List built an improbable business on ratings of household services companies.

But obtaining and publishing client ratings and reviews is much more difficult in the b2b world. This is particularly true when the vendor is relatively small compared to the client organization. Many large companies and government agencies refuse to provide testimonials, authorize news releases or participate in case studies simply as a matter of policy. Some even go so far as to write restrictions on any sort of publicity into their purchase agreements, or fire employees who publicly endorse vendor suppliers.

Some companies view their selection of vendors, and their particular methods of using those vendors’ products, as a competitive advantage and so don’t want to reveal their choices or methods to other market players.

And some organizations refuse to endorse vendors out of legal, regulatory or security concerns. For example, every bank hires security consultants to test its systems. But you’ll never read about a bank president saying, “We’re so pleased with the services of XYZ Security. They helped us identify some online vulnerabilities that could have cost our customers millions of dollars!” Not gonna happen. It occurs every day, but no one is going to talk about it.

So, what can you do if you’re a b2b marketer who has an abundance of delighted clients, none of whom can provide public endorsement? Here are seven possible tactics.

Blind case studies: write those case studies, just use generic descriptors (e.g., “a large telecommunications firm”) in place of the actual client name (e.g., AT&T or Verizon). Many clients will even agree to provide information about their implementation and results (ROI, cost savings, time savings, etc.) as long as neither they as individuals or the organization are identified.

These may not seem as powerful as “named” case studies (particularly when the client is a well-known brand), but other prospective buyers get this and will still attach credibility to the case studies—they probably have similar policies about publicly endorsing vendors within their own organizations.

Use cases: these are variations of case studies, focusing on a non-obvious use of a product or service rather than a particular customer experience. For example, if you sell software that is normally used by engineering departments but can also improve operations and reduce costs in human resources functions, a use case is an excellent way to describe that application, pulling in results from real-world customers—just, again, not naming them specifically.

Multi-deal news releases: private companies typically don’t reveal financial results, and if large customers won’t consent to any publicity, how can you earn the credibility that goes with strong business performance? One method is to periodically publish news releases with high-level details of recent customer wins. You can even include details like how you were selected over several other vendors or the types of results that a particular (described, but unnamed) customer organization expects to achieve with your product/service, based on the experience of similar customers.

Use statistics: write about your clients as a group rather then individual entities, for example: implementing your 1,000th customer system, hitting the  1 million user mark, or achieving 98% customer satisfaction. Or publish collective customer results, such as cumulative cost savings, online threats thwarted, transactions accurately processed, etc. If possible, get third-party validation for your numbers or offer to share your methodology confidentially in specific sales situations.

Ask for the possible: even clients who can’t agree to case studies or news releases may be willing to help in other ways, such as presenting at customer events, providing private references as part of sales cycles, or serving as internal champions helping to “sell” your product or service to other departments or locations within their own organization.

Build a thriving social network: encourage your clients to follow you on Twitter, like you on Facebook, and connect on LinkedIn. Then give them a reason to monitor and participate in these networks, e.g. by sharing helpful product usage tips and stories as part of your content mix. Prospective clients will check you out on social networks; the quantity and quality of interaction in those venues says a lot about your responsiveness as well as client enthusiasm.

Create a private customer community: again, clients who can’t speak publicly may be much more open within a controlled environment. If your product is one where customers are able to support each other, a private social community is a great way to get them talking. This doesn’t generally support new deals, but can help expand your sales within existing client organizations.

The key is to be creative. If you’ve got clients willing but not permitted to publicly sing your praises, find other ways to let their messages—even if not their specific voices—be heard.