Networking-site LinkedIn is being sued for allegedly "hacking" into its users' external email accounts and appropriating their personal information.
According to the filed complaint, LinkedIn allegedly sent out "multiple reminder emails" from the customers' own email accounts, advertising its services to their contacts.
"When users sign up for LinkedIn, they are required to provide an external email address as their username and to setup a new password for their Linkedln account," says the filing.
It's unclear exactly how LinkedIn would have sent the emails and the company has vigorously denied the claims.
"LinkedIn is committed to putting our members first, which includes being transparent about how we protect and utilise our members' data," a spokesperson said. "We believe that the legal claims in this lawsuit are without merit, and we intend to fight it vigorously."
The complaint suggests LinkedIn is actually accessing users' email accounts to send the messages, but it may simply be harvesting email addresses via its system to find contacts - which users have to agree to first.
"LinkedIn uses this information to hack into the user's external email account and extract email addresses," the suit said. "If a LinkedIn user leaves an external email account open, LinkedIn pretends to be that user and downloads the email addresses contained anywhere in that account to LinkedIn servers."
The technical detail in the filing suggests the users are taking issue with LinkedIn's contacts-sharing function, common to many social networks.
On signup, new LinkedIn users must associate their new accounts with a third-party email account. They then use that email account to log into LinkedIn, albeit with a different password.
Anyone already logged into their email account and clicking LinkedIn's contact-sharing tool - in order to "grow your network" - will receive a request asking whether they will share their contact information between the two services.
LinkedIn explicitly states that it will "not store your password or email without your permission".
But suit alleges that LinkedIn failed to ask for permission and simply transported the third-party email contacts anyway, though it's possible they simply misunderstood the function.