The other day, I wanted to add my signature for a cause I care about via an online petition. The site required people to submit their email addresses, so I entered a disposable email address. Otherwise, my personal email address could be spammed, added to mailing lists, or even sold by that vendor to other third-party vendors. The latter being one way people's personal email addresses end up in searchable databases.

But it's not necessary to submit your personal email address to any online site that demands it. Instead, create your own "throwaway" email address or use a free disposable email address service.

Throwaway Email Address

I'll use gmail as an example. I have several gmail email addresses: One is my main personal address that I check daily, another is a writing-business addy, yet another is a PI-business addy...and then I have a fourth gmail address, which is a throwaway. 

I use this throwaway email address for online registrations for organizations/services/whatever whose announcements or news I never want to see (or I can log in to that throwaway account to occasionally check them out). You can name this email address whatever you want (such as registrationsonly@gmail.com).

Gmail lets you forward emails to other gmail accounts, so if you decide you want to regularly see those throwaway emails, you can set up forwarding from registrationsonly@gmail.com to your personal gmail.

Disposable Email Address

A disposable email address is just as it sounds -- it's an email address that gets tossed, like trash. On these disposable email sites, addresses self-destruct after a short period of time.

Below are three disposable email services -- best of all, they're free. Some also offer paid premium services for snazzier features.

Guerrilla Mail: My personal favorite. Great for online registrations for sites that require an email address and then send you a confirmation link that you must click. Guerrilla provides a temporary inbox so you can do that, then the inbox gets automatically zapped a short while later (currently, Guerrilla keeps the inbox for an hour).

You don't need to register to use guerilla's services, just visit guerrillamail.com when ready to create a temporary email addy.

Mailinator.com: What's cool about mailinator is when you're on some site that requires an email addy you can make one up on the spot using the @mailinator domain -- for example stirnotshaken@mailinator.com -- then go check the email later. Yes, that's right -- the instant you write the xxx@mailinator.com address, it is automagically created on the mailinator site. Note: Maininator is for receiving mail only. You cannot send mail from mailinator. So you can't use mailinator for online registrations that require you click a confirmation link. Emails auto-delete after 12 hours.

Mailinator requires a Google sign-in and all email is publicly viewable (someone would need to know what email address you've set up, of course). There are also private options, some free, that remove your email messages from the public domain.

TrashMail.com: New customers are required to register a real email address before using this service. The reason I use disposable email services is because I don't like giving away my personal addresses, but the plus for doing so with TrashMail is it offers more features than other similar services. It also states in its privacy notice that it does not sell any customers' personal data, including their email addresses.

Features for free TrashMail:

• Customize your email address
• Choose from a variety of domain names
• Address masking on reply
• 300 active, disposable email addresses
• Filter incoming messages with a CAPTCHA
• Set number of times the customized trashmail addy is forwarded to your real email address
• Browser extension for Chrome and Firefox.

For $12.99/year, you can have up to 2500 active email addresses, no alias expiration and unlimited forwarding to your real email address, send emails via an SSL-secure webform, and email support. 

Some Sites Block Disposable Email Domains

Personally, I have not yet had a site block a disposable email address I used, but others have complained of this happening. Several of those people suggest using spamgourmet.com, which requires customers enter their real email addresses for registration (customers then create bogus email addresses that they use on forms, etc.. This bogus email then forwards emails to the person's real address).