I have seen people that run searches on twitter looking for leads. Looking for people ready to buy phones.. that "can't wait" for this or that. I'm not sure what algorithms they use. I suppose you could also look for people posting links to product pages. You could create your own bit.ly links and look for others sharing your page, things like that. I suppose it depends about the popular stuff in your locale for a brick & mortar shop.
It depends on how you get your followers. If you are following "TeamFollowBack" and the type of follower to increase your Twitter followers, then no, these people are trying to sell their own stuff and are less than interested in what you have to offer, however if your followers are coming from some quality traffic that you've posted then there is quite a bit of potential for traffic, especially if one of those people Tweets about your stuff and he has a huge loyal following already.
Where’s the profit? Twitter for business, I believe the top uses, from highest profit to lowest profit are: 1.Consulting, education and joint ventures specific to making your business more profitable (networking with others in your field). 2.Finding prospects to sign up for your mailing list (converting them later to paying clients/customers). 3.Building your brand and reputation. 4.Promoting offers, products and services.