Information of 500 million LinkedIn users posted for sale online; company says it was not hacked

Data from about half a billion LinkedIn users was posted for sale online, but the company says it wasn’t hacked, and that the information was taken only from users' public profiles.
The company says the post was made on a website popular among hackers.
Some of the data was aggregated from other websites, and according to the company, it did not see any private information in the post.
A cybersecurity site says the information includes users' names, e-mails, phone numbers and professional titles.