The SSL PKI has been in use and implemented for 15 years now to secure online communications. From its initial proprosals and immediate growth, the need for secured online communications has been met with challenges. The infrastructure and protocol itself is showing signs of wear, with multiple attacks and corrections to the scheme itself. And in its 15th year, an alternative to the Cerificate Authority infrastructure is finally being given some competition with the release and debate around Convergence, an open source alternative to the current system of Certificate Authorities. Feel free to right click and download for the full sized version; the graphic below provides a list of some of the major events for SSL/TLS PKI in the past 15 years.
Certificate authorities Firefox Google Chrome Microsoft Internet Explorer Public key infrastructure Verisign