Business social network Spoke is launching what it says is a better way for businesspeople to connect to each other. It has put together a database of more than 40 million people in the US and starting today it will let you email any of them. Caveats to the previous statement, below.

The San Mateo, Calif. company isn’t giving away 40 million email addresses. Instead, it has its own email system built into the site, not unlike LinkedIn’s InMail program. You find somebody you want to contact through Spoke, then you send them an email through the email feature, called ConnectUs. The difference between the email programs offered by Spoke and LinkedIn is that LinkedIn only lets you email people you’re connected with, or are introduced to. With Spoke’s ConnectUs, you can email any other person in its database.

The business problem that Spoke is solving, chief executive Frank Vaculin tells me, is that businesspeople want to connect with anyone, not just people in their own network.

What about people who don’t want all this email? Let’s say you’re Microsoft founder Bill Gates, who stopped using Facebook earlier this year because he was getting overwhelmed by friend invites, pokes, messages, and no doubt application invites. If you use Spoke and find yourself getting bombarded by unsolicited emails, you could just turn the ConnectUs email feature off.

Which begs the question of how Spoke knows all these email addresses, in the first place. After all, LinkedIn, the most prominent business social network in the US, has around 21 million monthly active users (and is growing fast). Spoke has put together its user database over the last four years, Vaculin says, that includes information about people, like where they work as well as email patterns among people at companies. One way that Spoke has gathered this information is through its toolbar for Microsoft Outlook. You install the toolbar and use it to validate email signature files. So, if somebody you know at your company emails you, you use this toolbar to tell Spoke that they’re really your colleague. Also, Spoke scrapes the web for email addresses; in this sense, Spoke more closely resembles ZoomInfo, which also automatically aggregates information about businesspeople.

Another way Scope plans to block spammy emailing behavior: The first three emails you send are free, then you have to pay a fee.

I’m not sure if Spoke will be able to challenge LinkedIn, or other services, like executive-focused networking services offered by Hoover’s, or European rival XING. The idea of secure emailing without networks is at least interesting.