does I-Mac need surf easy plug in USB privacy?

You operating system is not a Classic Mac OS, if it has X in the name.

More important than any hardware or software is a means of backup:

https://discussions.apple.com/docs/DOC-1992

There are numerous ways of browsing the net privately. Some restrict online purchases, while others do not. In general, the physical security of your computer is one which determines how much you need privacy added. Note, if you use a wireless network, you should have WPA2 encryption enabled and not WEP, or no password on the wireless, and all the computers on the network should have it. If you do have an older Mac with only Classic or some version of 10.4 or older, an ethernet/WiFI bridge is better than an original Apple Airport card for wireless connections, since the original one does not have the WPA2 encryption. That encryption is needed if anyone could drive by within 1500 feet (500 meters) of your connection and connect onto it. And remember any e-mail that sounds too good to be true probably is. Do not trust peer2peer software, as frequently not only illegal but pirated copies of non-release software find their way onto those networks. Do not download any Mac optimization software. The worst of these is MacKeeper:

https://discussions.apple.com/docs/DOC-3036

No system cache or prebinding software should be used without first having at least two backups of your system that won't be affected by any attempted repair.