You may be “shedding” personal details, including e-mail addresses and other contact information, without even knowing it unless you properly configure your Web browser.
In your browser’s “Setup”, “Options” or “Preferences” menus, you may wish to use a pseudonym instead of your real name, and not enter an e-mail address, nor provide other personally identifiable information that you don’t wish to share.
When visiting a site you trust you can choose to give them your info, in forms on their site; there is no need for your browser to potentially make this information available to all comers
Also be on the lookout for system-wide “Internet defaults” programs on your computer (some examples include Window’s Internet Control Panel, and MacOS’s Configuration Manager, and the third-party Mac utility named Internet Config). While they are useful for various things, like keeping multiple Web browsers and other Internet tools consistent in how the treat downloaded files and such, they should probably also be anonymized just like your browser itself, if they contain any fields for personal information. Households with children may have an additional “security problem” – have you set clear rules for your kids, so that they know not to reveal personal information unless you OK it on a site-by-site basis.