not really
No, Eraser cannot protect your online identity. It will only erase sensitive data that you command it to via a right click on your mouse (i.e. the "erase" option). My suggestion is that you use Yahoo.com as your homepage in your browser. From, Yahoo, you can download an anti-spyware plug-in for your browser that will protect you from the mentioned problems (click on the utmost righthand area of the screen on the text that says "Get Yahoo toolbar with anti-spy." Beyond that, do not reply to e-mail addresses that you do not recognize.