From the article:
"...using systems that were first compromised by infected e-mails sent to company executives."
LinkedIn members that share a group can exchange messages, and request to connect.
Do Corporate Executives feel safer connecting to strangers on LinkedIn?
Would they be more likely to click a link supplied by a LI connection as opposed to a random email message?
What about IT policy at your company. Your system administrators implement safeguards to check incoming email, but when high-profile Executives communicate outside the company IT infrastructure how do you protect them and the company?
*Note: The linked article is not about LinkedIn, it describes a common exploit used to breach company Internet security.