You may not know this, but there are six magic words that make phony social media experts disappear. As with all such incantations, you have to get the words exactly right. Here's how it goes:
"Show me five things you've done."
If your expert is still there, feel free to explain what you mean. You can explain that you'd like to see examples of social media efforts they have completed for five different companies. You can explain that the companies sponsoring these efforts don't need to be in your industry, but they should be comparable to yours or better in terms of size and brand recognition. You can explain that these efforts should not be in development, or coming soon: they should be ongoing or completed. You can explain that these efforts must be successful by at least one measure -- they engaged thousands or hundreds of thousands or (preferably) millions of users.
If they are still there, and they still can't answer the question, you may need to ask them to leave. Even magic spells don't work on some of these folks.
But seriously: it's important to know whether an individual or firm has experience in what works, or just ideas about what might work.
Just to be clear -- there's certainly nothing wrong with being a pioneer. And in new disciplines like social media, experimentation can be good, even necessary. But you should approach a project very differently -- and invest very differently -- if the project is a wild guess or a sure thing.
If you don't know the difference just say, "Show me!"