It's not easy to remember which services you signed up for in the past. If you need a little help tracking them down so you can delete them, Lifehacke reader Mike.Sims recommends using the username search site KnowEm to hunt down your accounts.
We've talked about using KnowEm before to search for username availability, but it's much more useful as a way to search for lost accounts. Just type in your most used usernames, and KnowEm shows you where they're registered. From there, you can go through and delete your old accounts with ease.
If you need even more help finding accounts, we have you covered there as well. Once you track down the sites you have accounts with, you can use a service like AccountKiller to go directly to the account deletion page.