Is this something to do or worry about?
The answer is yes. Java is problematic, especially in the browser, and is the number one vector of disease for computers. If you don't actively use Java, you should get rid of it from your browser.
My recommendation is to use Firefox as your main browser for all general web-surfing, and disable Java from Firefox. Then IF you have a site that requires Java, and you trust that site, run that site only in MSIE and all your other browsing (Facebook, Google searches, etc) in your security hardened Firefox.
To disable Java in Firefox (for Windows PCs): open Firefox and click Tools menu --> Addons. Click the Plugins tab, locate each of the Java plugins, and click the Disable button for each. Restart Firefox and you're all good!
Mon 20130114 Updates:
- http://www.scmagazine.com/java-zero-day-infections-pick-up-steam/article/275818/?DCMP=EMC-SCUS_Newswire
- https://www.securelist.com/en/blog/208194070/Java_0day_Mass_Exploit_Distribution
