Been looking, and not finding, so anyone know of adblockers that will definitely work on Safari 5.1.7? Adblock? Adblock Edge? uBlock? Anything?
Wasn't it discontinued for windows? Are you using it by choice? Ad Muncher will work... http://www.admuncher.com/download I recommend a different browser if you can choose.
Why would you use a legacy outdated browser with security holes and website compatibility issues? Anything that applies system-wide, whether that is DNS, HOSTS, proxy, VPN, or even firewall will work.
There's this: http://lifehacker.com/5561134/adblock-for-safari https://getadblock.com/ But tbh, I wouldn't bother. It's released almost 3 years back and no longer has any updates.
Not only will it be a security issue, it will also be a privacy issue, as it doesn't support the latest TLS 1.1 and 1.2 protocols.
For simple surfing, TLS is a luxury, not a requirement. As for security, running any browser with reduced rights via Sandboxie is enough for simple browsing. If you want to do online banking, make it hard on Big Bro, etc., then Safari, and legacy versions of IE or Firefox are obviously a poor choice. For this, there are many hardened browsers, or better yet, JonDo LiveCD. Safari 5.1.7 and legacy browsers are useful to help defeat browser fingerprinting, and okay to use on a limited basis.