Ponder something that most marketers get wrong. You have a bunch of customers, right? Wrong. What most classic marketers don't realize is that "your customers" are also your competitors customers. Add this concept to your SWOT analysis.
Worse still. In many cases your best customers are also your competitors' customers. Even in market research. For example, if you have been doing market research in the Portland area and you have not done market research for HP, Microsoft or Intel, then you aren't really a player. I remember one particular incident where a young project manager called me from Microsoft and said: Hi I'd like a 400 case telephone surveys. I said, great, I'd love to help, when do you need it by. He said tomorrow, it says so right here on the schedule that I need it tomorrow. He didn't even have a questionnaire yet.
If you are a restaurant, your customer probability-wise has made a purchase at a fast food restaurant. Over 90% of the US population eats fast food and they do it at different restaurants.
Some big customers, like the earlier mentioned high tech firms, do spread the work around so they have more options. Exclusive arrangements are very rare.
And if you are a market research buyer, beware of my jackass competitors. I once had a guest speaker at one of my University Market Research classes that was doing proprietary research for two top competitors and the competitors didn't know. This is only partly his fault - because of confidentiality reasons he was afraid to mention it because that would be a violation of his NDA. This stuff ticks me off almost as much as the competitors of mine who sign up for linked in with me so they can go after my clients. Might as well have a Demopublican Convention at times.
Research can show you opportunities and threats, such as the fact that your customers are buying a very similar product to yours from your competitor xx% of the time.