If you want to pretend to be someone you're not while making a real phone call, there's an app for that. Fake Voice will mask your voice, making it sound like someone else's.
A Windows application also called Fake Voice does something similar.
There's also an interesting subcategory of smartphone apps that spoof your GPS location, making it look like you're somewhere you're not. These include Fake GPS Location on Android.
If you're an Android user and want people to believe you're an Apple user, you can use the Fake iPad 3 Screen app. (Make sure your Android tablet is rectangular with rounded corners.)
Some software lets you pump pre-recorded video into webcam software to make it seem like you're someone or somewhere you're really not. PerfectFakeWebcam and Fake Webcam are two of the more popular options.
A download called Pwn Mail spoofs the sender address for outgoing email. That means you can send email, but the recipient thinks it came from whomever you specified.
Some lying software is just plain goofy. For example, an iOS app called Fake a Fish lets you take one of your actual photos and add an image of a big fish, so it looks like you caught it.
FatBooth for iOS enables you to a modify a photo of someone to make him look fatter.
A site called iFakeSiri will let you type in the dialogue of a fake conversation between you and Apple's voice assistant, Siri. The site will produce a convincing screen-capture spoofing the conversation.
Most of these, of course, are for pranks and fun. But another site is very serious about helping you flat-out lie.
A service called the Alibi Network will actually tell just about any lie you want to tell, and it will do it by email, fax or phone. The service's professional liars are standing by to call your spouse or boss. When they call, they'll leave a number for callback, and the caller will get a voicemail message. They'll even print certificates of achievement, showing that you attended a seminar or passed some test.
Is all this computer-aided lying unethical? I think the answer, obviously, depends on how people use them. Any of these could be used for good or ill.
The important thing is that we all know these products and services exist, so we're not fooled by such software and services and can focus our skepticism properly when people provide "evidence" for things that are just plain lies.
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