Chris Ibsen wrote:
All these people love to try an scare you into converting by saying OMG your computer will be toast if you hit one bad site. It could happen to any computer on any OS X.
That is not at all true. Currently, there is no known way to install something via drive-by download on up-to-date versions of Safari. Your computer absolutely will NOT be toast just from visiting a bad site in Safari at this time, based on any currently available information.
Safari in Snow Leopard, however, hasn't been updated since 2013. I haven't kept myself updated on possible security issues with Safari in Snow Leopard, because I haven't used Snow Leopard in many years, and don't even own any machines that can run it anymore. However, there is a distinct possibility that some of the vulnerabilities that have been fixed for newer versions of Safari in the last two years could also be a problem for Safari 5.1.10 in Snow Leopard, but were not fixed.
Thus, it is possible that drive-by vulnerabilities exist in Safari on Snow Leopard. The only thing keeping you somewhat safe from such things is the fact that Snow Leopard is a shrinking target, probably not worth attacking by most hackers.