Twitter can distract and make you endlessly digress and from a business perspective - take the wind out of your passionate sales.
It's not that Twitter is a bad thing for business, per se, but it can cloud focus on the core variables that make a business work. Closing deals, invoicing and getting paid. This, of course, all comes after creating a product or service, packaging it and selling it.
I know there are so many Twitter positives for certain types of businesses but from my cursory look, these are service business, and more than that, they require a certain type of digital networking element to them. They are also often photographic or design in nature! The difficulty arises when people look at Twitter and think they can force any business model down its 140 character throat. Very often you can't - and you shouldn't try. You can do more harm than good to your fragile brand. It's worth stating again. Twitter and social network marketing is all about digital networking. If this isn't a big need for your business. Hold back.
But, there are, of course, some super exceptions. Businesses, like that of www.TheAdventureTeam.co.uk (don't forget the 'The'). This is a community building adventure holiday company, from Gortin in Tyrone. With more followers (4,474) than friends (4,160), this small company uses social media wonderfully. Embracing Twitter, Blogs and Facebook, it goes where people online gather, and invites them to take a community building adventure. As a reviewer of social media use for businesses, this is excellent, but as a lover of good web content, it works for me too. The tweets call for fundraising for Haiti, express regrets at a friend's loss, show care and interest in others, and pass on news... taking care to connect with those who connect with them. This all has a great community vibe to it. The service itself, when you click through to the site is also compelling, with incredible deals for adventures, accommodation and food.
So I'd say do what works, go where your market goes, but do it cleanly and efficiently and don't Twitter about it unless you've got a business for tweets. If you do have such a business it'll work and you're missing a trick if you're not trying it. You have customers waiting to connect with you, if you'll just connect with them.