Wrong AuthorYou'll likely be shown examples of social media success. The vendor implies they participated but this isn't always true. One firm showed Facebook pages for well-known companies and said this was the kind of work they do. That does not mean the vendor did the work shown.
There's a related caution. Are you shown the sources for videos, graphics and other content? Sometimes the credits are suppressed, which is disrespectful to the creators and misleading. You might think the vendor created something they nabbed from YouTube.
Wrong ExamplesWhat works for Starbucks, Zappos and Coca-Cola isn't the right or only answer. It's not as if fools have marketed Tim Hortons and Pepsi to the edge of bankruptcy. What works for other companies need not work for you.
Wrong CountryWhat works in the US may flop elsewhere. Wal-Mart left Germany. Are you shown examples suited for your country?
Wrong CategoryWhat works for mass market products may not work for niche products or intangibles. For instance, buying insurance is not as simple or routine as getting your daily coffee. If you choose the wrong brew, the cost is low and damage minimal. If you spill the stuff and stain your clothing, you might sue because there's no warning that this might happen. (Note: this is not legal advice. Consult your lawyer before seeking lawsuit windfalls.)
Wrong TimeframeA search engine optimization vendor said that getting on Google's first page takes six months. That's a nice way to get a contract for half a year. You can get on page one anytime based on factors like your content (though Google Realtime search is currently unavailable). You could also buy Google Adwords if earning attention takes too long.
Fish or FishingIs the vendor teachingg you to fish or selling you the catch of the day every day? There are often low-cost, easy-to-use, easy-to-implement options that will give you reasonably good results instantly.
Say you want to gauge how your company is mentioned in social media. Why not start with Google Analytics, Google Alerts, Twitter searches and Facebook searches. They are all free. Going beyond, there are other tools like Google PostRank, Klout and PeerIndex --- free or inexpensive. As your needs and understanding grows, you can upgrade to fancy dashboards with nice graphs.
Once the novelty is gone, what actions will you take based on the data you receive? If you aren't likely to do much, how does gathering more help? If your primary concern is crisis management, do you really have a problem that Google, Twitter or Facebook won't quickly spot? You connections with phone or email are part of your early warning system too.
OmissionsWhat's left out is often matters. How do you know what's missing? Seek a vendor that's an advocate for customers like you. You'll see this in how they educate you for free via text, audio or video.
David Ogilvy's brilliant 1,900 word ad from the 1960s shows customers how to advertise. Do you think education hurts sales?