Twitter is a great tool for some of the reasons mentioned above. It does take time (months) to build a following of current and more importantly, potential customers. I have a slightly different view of the horse people/ non owner example. Some of those folks eventually will have a horse and be in the market for your product. You have already done the groundwork and they will hopefully come to you first when ready to purchase. We call them Prospects rather than Customers. You need to look at that group a little differently and not dismiss just because they won't buy today. People are more apt to buy from someone they feel they have a connection with. Especially if it is expensive and/or custom. Build it into part of your overall plan and remember it's low cost aside from just 5 minutes a day to post.
A great book on the whole subject of social media marketing is "The New Rules of Marketing and PR", by David Meerman Scott, which coves blogging, Twitter and other channels to help your audience find YOU, instead of the other way around. Smart, eh?
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