Scope of SSL
SSL puts an additional overhead on a web server and a user's browser, and so in the past it has tended to be used only in places where sensitive data is transferred, especially for credit card transactions. There was seen as little point applying SSL to all traffic such as when a casual visitor is browsing the site, or a search engine is spidering it.

However, in recent years, SSL has become more widespread. Many web sites such as Google use SSL by default, and the revelations by Edward Snowden of pervasive internet surveillance by western security agencies have further highlighted the issues of eavesdropping and user-privacy. In summer 2014, Google indicated that it would start to give slight preference in its results to sites running SSL, which is likely to see a surge in the take up of 'always on' SSL.