We recently found some interesting information (at CSOonline ) about a study that examined involuntary leakage of information via peer-to-peer file sharing networks at a group of large financial institutions. What they found wasn't pretty! 

The paper (PDF) found end users are often lazy or poorly organized, leading to internal company documents as well as partners' documents being revealed

"For one bank, we found a spreadsheet with 23,000 business accounts including their contact names and addresses, account numbers, company positions, and relationship managers at the bank," the report states. Also found: one bank's security review process manual.

The researchers found that criminals actively search P2P networks looking for information to exploit.  One other conclusion: Big firms have to work a lot harder to safeguard themselves against P2P-oriented leaks than smaller ones.

Apply to you?  Check out Akonix and Sophos - two differing but complementary technology approaches to the problem.