you mind displaying your username to see how you use it? we use it for very light marketing and haven't found any noticeable success from it, though it takes no time extra as i usually update whilst in car so nothing lost. I do plan on increasing how i use twitter to see if it's really worth continuing with it.
what i find hard to decide is how formal to be with it. i try to be natural and see how customers respond but often i see other companies just saying something like "need a carpet clean?
www.dot.com" etc and it makes me wonder if this is the norm