Jeremiah Owyang raised some interesting thoughts over at his blog about 7 Questions Some Brands Are Asking About Twitter . To my great surprise we haven't had anyone talk on the news blog about how we're using twitter at Atlassian, so I thought I would give Jeremiah's questions a crack and hopefully provide an insight into how businesses can use twitter based on our use case.

1. Should we create multiple accounts for different divisions? How should we name them? How should the content be different?

We naturally ended up with multiple twitter accounts at Atlassian, and that's just the way we like it. If everything was coming through one account our followers would be bombarded with tweets that weren't relevant to them.
@atlassian is our general company account. It is used to send out tweets about our blogs and products. We use to answer any questions directed at that account, also to give updates on conferences that we are attending. Anyone from the company can issue tweets from this account as the login and password are freely available on our internal Confluence extranet. However most people prefer to use their personal twitter accounts when dealing with customers. Our golden rule of thumb is that the corporate account is not a person, and therefore shouldn't be expected to behave like a personal account. It's run by the marketing team, and we're up front about that on our twitter bio.
@atlassiansummit, @jirastudio and @cloverallover are accounts that are used for more specific sections of our customers. We're pretty sure that most of our followers don't want to know when JIRA Studio is scheduled for maintenance, unless they are Studio customers. Likewise we try to keep Kitty the emailbot's alcoholic tweets away from our general followers.

It is also worth mentioning that a lot of Atlassians are running their own individual accounts, including our Fearless Leader and CEO, Mike Cannon-Brookes (@mcannonbrookes).

2. Is it ok to just tweet out news on our main corporate account? Or should we be conversational?

This depends on the individual company, for us the answer is no.
If a customer or a potential customer called you up on the telephone and asked you a question would you hang up on them? I'm guessing not, you would direct them to the correct department and try and help them out.
When we first started using the @atlassian account we did a lot more broadcast type announcements feeding through information from our blogs and press releases. We find we are more conversational now as more people join twitter and see the @atlassian account as another avenue for customer service and interaction.

3. How do we get our corporate reps (sales, product teams) to use this tool, and be conversational?

Our community and media advocate Laura sent out a request to staff over our internal blog encouraging staff to sign up. Twitter use has naturally grown from there as staff have added their own accounts as a way of dealing directly with customers. Because there were so many interesting conversations happening people naturally wanted to be involved. It didn't take a lot of convincing to our sales and support guys that twitter is just another avenue to talk about Atlassian to our customers. Every department now has individuals on twitter - tech writers, product managers, developers, support heroes, design guys, technical sales, and naturally the marketeers.

4. Should we follow folks? If so, what's the protocol? Should we only follow folks that follow us? We don't want to appear like 'big brother'

We use @atlassian to follow people who follow us, we manually follow back to make sure we aren't just following spammers. However we do not actively seek out people to follow from the @atlassian account. At this stage there is more likelihood that individuals will actively follow customers, contacts or naysayers depending on their personal area of interest. We're still working out how to monitor and not be too over eager and 'overtwitter' from personal accounts to customers.

5. What are the tools to use to manage multiple authors/tweeters?

Seesmic Desktop seems to be the choice at the moment with the Atlassian twits for multiple accounts.

6. How can we find other examples of B2B twitter examples?

You're looking at a detailed one right now.

7. How should we brand our Twitter backgrounds images?

Our main accounts are aligned with company branding and like all our eye candy are designed by our fantastic inhouse designer - Jason. For example the @atlassiansummit background lines up with the Atlassian Summit website and all our marketing collateral around that.
We have also been known to change out our twitter backgrounds if we're running a special campaign that we want to promote - for Earth Hour earlier this year we pimped out a new twitter background.