I am developing a web application.
As part of my marketing attempts, I am trying to send messages to different companies that might have interest in my product.
Unfortunately I only have an email address, and a vague title.
How can I send an elevator pitch through such an email, that will still catch their attention?
It's highly unlikely that this is going to get the desired result as a direct marketing assault. At best, it might be ignored, at worst you might sour a potentially good business relationship by sending unsolicited e-mail. One of the hardest things to do is to develop an effective network into potential customers, because such development is often indirect and time consuming.
Is the product a technology push or is it a pull from the customer side. Technology push is far harder to do normally, and without a developed network it is going to be very frustrating. My recommendation is to consider all the prospective customers, and ask yourself: which of these would represent a key customer in terms of feedback for product development and would act as an effective reference for other customers in the market space. Which customers might influence future sales through their networks? These are the ones you will want to specifically target. Learn as much about them with regards to their needs for your product, craft your pitch specifically to them and then make your pitch. But you have to know this customer and what they need and show that you've done your homework. I get at least ten calls a month with some product that is being pitched, and they always fall on deaf ears because the person making the pitch doesn't understand the nature of my business. I don't need them to understand the intimate details, but 5 minutes on the web will give them a sense of the business model. Showing that some homework has been done will at least get my attention and differentiate them from 99% of the others that call, and at least gets a toehold. Bottom line: email address and vague title are not going to cut it.
If it is technology pull, where users are actively scouring for the solution that you may provide, then your marketing approach might be easier, and you can follow the procedure above and try to reach the potential customers through the methods they're using to generate solutions (trade shows, advertisements in trade journals, direct mail, mailing lists through industry partner sites,etc). You still need to understand those key customers, and think of ways to get your pitch to them in a targeted way, but the probability of gaining traction in the customer space is much better.
Beyond that, start with standard elevator pitch protocols... call out the customer PAIN (and it better be real pain) and how you are going to solve that pain. Follow through by differentiating your solution from existing options, and use that opportunity to fill in who you are, what you're doing, and why YOU are the one that can make the pain go away.