Dug away in an article about Twitter in the Wall Street Journal:

Mr. Stone says Twitter recently hired a product manager to oversee the development of commercial accounts. The accounts would offer users more features in exchange for a fee, but Mr. Stone says Twitter hasn’t set a launch date for them.

So there we have it, then. The business model will be paid accounts. And maybe advertising too — who says there has to be just one way of making money? Right now it seems likely that those little text ads that have appeared in the top right corner of your Twitter homepage will soon be sold. Right now they’re up there for free — which I assume is part of an experiment into how many clickthroughs they can promote to potential partners.

But I sense advertising will be little more than a nice slice of the bigger pie: the pro accounts.

Offering special accounts to businesses is a way of making  a shedload of cash while still managing to retain its massive userbase.

I wrote about what a pro account could involve a little while ago — and it seems like some of those predicitons are going to come true, namely this thought:

Say you’re a publisher. You want to reach people in as many ways as possible. Currently, you have to just hope they’re reading their feed and they spot you. How about, for a fee, Twitter gave you the ability to allow any user — not just those with Personal Premium accounts — to subscribe to SMS updates from your feed.

Your fee would depend on two things: How often you post, and how many people subscribe. In other words: how many texts are sent. In the same way that websites have to assess their bandwidth costs, Twitter publishers with Publisher Plus priveledges will be able to monitor their reach — upgrading if neccessary.

I also suggested a personal pro account — something I still feel would work. But, from a public relations point of view, Twitter are wise to begin by charging the rich people.

Since then, I’ve been thinking a little more about how Twitter can make money and, if they go ahead with pro accounts, what should be in them.

In my job as co-editor of the BBC Internet Blog, part of my day-to-day task is to monitor what is being said over social networks. Twitter being the most useful. To do this, we have a Pageflakes account which searches various terms like “BBC” or “iPlayer” and so on. I keep an eye on this.

A pro Twitter account should do this for me. It should allow me to track RT’s relating to the BBC. It should allow me to have a league table of most linked to sections of the BBC website. It should have a Tweetgrid-style interface built in to a pro account control panel which I could use to monitor things as I do now — without the need for Pageflakes.

The pro account should give me statistics for my Twitter feed. As a normal user, sometimes I get a flurry of follows during the day and I’m left asking them where they came from. Sometimes I get a reply, sometimes I don’t. Twitter should be able to tell me — if I was running a company I’d want to know if I was being followed as a result of negative or postive press.

But most importantly: a pro account holder should have the ability to send text messages to all their followers (if they opt-in, of course!). The value of that really cannot be understated.

Update:

More about the plans on Silicon Alley Insider:

Commercial entities like Whole Foods, Starbucks, Mission Pie, 52 Teas, JetBlue, even the Korean taco truck guy are all on Twitter—users and businesses alike are finding value.

Our question is, how can we help? What can Twitter offer for a fee that will improve the experience? Will it be account verification? Will it be lightweight analytics? Will there be opportunities for introducing customers to businesses on Twitter.

So many questions. But the key is to understand that Twitter will remain free for all to use—individuals and companies alike. We are thinking about simple business products that enhance and encourage what is already happening.