How to find competitors's customers

Use Twitter. Check out 7 Sneaky Ways to Use Twitter to Spy on Your Competition. Here are some ideas:

• Follow your competitors' followers. Many people on Twitter will follow companies they are either interested in or are a current customer of. Engage some of their followers if they show interest in your competitors' products.

• Follow your competitors. Find out what they are saying and who they are saying it to. Odds are you will discover your competitors talking to their customers, or potential customers. Then follow those people and engage them yourself. If you don't want your competitors to know that you are following them, you can create a private list that only you can see. Put all of your competitors on that list and now you only have to look in one place to see the latest conversations your competitors are having.

• Search Twitter. Search on Twitter for the names of your competitors and the names of their products. See who is talking about them, who is happy with them, who is not happy with them, who has questions that you might be able to answer, etc.

Search your competitors' websites. Some businesses will give away customer information on their websites in the form of either customer testimonials, or in the case of B2B, company names. Of course this won't be an exhaustive list, but it'll get you started.

DoubleClick Ad Planner is great for this. You enter a competitor site and find out what other sites visitors of that site are likely to go to, then use Google AdWords to create managed placement ads for those sites which offer ads that can be targeted by Google AdSense.

Here's my two cents on some techniques one can use in order to find competitors customers. Please keep in mind that your description is very superficial, thus some of the things I state may not apply or may be paths you've already explored.

You could identify a pattern in your customers and infert it from there. For instance, if your customers are mainly insurance companies, then you should reach other insurance companies.

You can try searching in social/professional networks for people who's using your competitors software, since usually people write that kind of information in their resume.

You can try talking with some of your current customers, since people with similar interests tend to connect. People change jobs but, usually, stay on the same kind of business, so if you get someone that came from company A, maybe he/she used your competitors software while in company A.

If you find out where users usually hang out (support grups, linked in groups, etc.), you can reach them there.

If the product's expensive, i.e. it'd be worth their time to answer your query, there's nothing wrong with phoning your competition posing as a prospect and asking for testimonials from their users as part of the conversation. I wouldn't make it too obvious what you were up to though in case they cotton on, hence the need for a bit of padding around that key question.

Figure out where your competition is advertising, and place some test ads there.

Take out google ads on people searching for your competition.

Ask your customers how they found you, and do more of whatever you did that led them to you.