Skype-to-Skype calls to other users are free of charge, while calls to landline telephones and mobile phones (over traditional telephone networks) are charged via a debit-based user account system called Skype Credit.
Some network administrators have banned Skype on corporate, government, home, and education networks, On 12 September 2005, e Bay Inc.
Silver Lake, Andreessen Horowitz and the Canada Pension Plan Investment Board announced the acquisition of 65% of Skype for $1.9 billion from e Bay, which attributed to the enterprise a market value of $2.92 billion.
Microsoft bought Skype in May 2011 for $8.5 billion.
Users may have more than one account; it is not possible to count users, only accounts.