One of the handy conveniences of most cell phone plans is the fact that Caller ID is built-in. When the phone rings, you know who's calling. Typically, if that number matches one of your contacts in your address book, you'll see their name come up; otherwise, you'll at least get a phone number. But who is that unknown person that's calling? Or maybe they've blocked their number, but they left you a voicemail message that tells you to call them back just as soon as possible, but didn't bother to let you know who they are.
800notes.com is a free service that can help you answer those questions. Their database is built from user entries, people like you who got a call from goodness-knows-where. You can read what other folks had to say about the number—maybe they figured out who it is, or at least they can tell you what they heard when they called it back—and leave your own information as well. Now the spammers and scammers can't hide, and you won't feel so bad about not getting right back to them.