As the name indicates, your 10-Minute-Mail account is only valid for 10 minutes (you can extend this if needed). That is normally plenty time to validate the address. There are two big disadvantages with this system, though:
- Sometimes you may actually want to get email from the online service, for example if you forget your password and they email you a new one. I don't know if 10-Minute-Mail lets you re-activate an email address when you know it is about to receive email you want to read?
- The email address generated is not very easy to remember (e.g. firstname.lastname@example.org). If your email address is your sign-in/account name, you're stuck remembering a seperate, cryptic email for each service.
An alternative is http://www.dodgeit.com/, which provides free, receive-only email accounts. You can choose the address (good), and subscribe to a RSS feed to get notified when new mail arrives (nice). A slight downside is that since everyone shares the @dodgeit.com domain, you probably won't be able to get email@example.com or firstname.lastname@example.org.
A solution that myself and a few friends use requires having your own domain (quite cheap), and having the domain set up to allow "catch-all" email forwarding. The way this works is that any email received by you domain that doesn't match a real account is forwarded to a real email address you specify (and that no-one can see publicly).
So, if you are signing up with CoolNewStuff.com, you could use an email address of CoolNewStuff@mydomain.com. Then, the few initial emails you get from CoolNewStuff.com would be sent to your real address. If at some point you start getting spam sent to this email address, you can filter it out easily.
Why not just use a single fake email address for all your online services? So that you can figure out who to blame if your account starts getting spam (usually this means the company sold your information, is spamming themselves, or has been hacked).