The same scams now exist online; non-delivery of auction or mail-order merchandise advertised on Internet sites is a common complaint.
Another variant involves shipping merchandise which was never ordered, obtaining a signature on delivery (or even COD), demanding payment for the items on the basis that they were signed for at destination.
Promotions selling services or data delivered entirely online are also particularly high-risk; if the promoter in question refuses to deliver as advertised, a fraud may be much more difficult to prove than if the seller is obliged to ship a parcel which requires a signature at destination.
Online schemes claiming that "a hot female escort will give you access to her entire pornography collection on some Internet site if you send a money order to a drop box in Barrie", if payment is accepted by postal money order and the product never received, would also qualify. The original solicitation is made online, the supposed product claims to be delivered online, but use of the mails at any point (such as to receive money or negotiable instruments) could easily qualify such a scheme as mail fraud.
So begins the wording on some rather slippery documents which look like they're bills or invoices even though they're not. The wording of the disclaimer is taken directly from the US Postal Service Domestic Mail Manual; the intent is to be able to claim that this document is not a fake invoice while still retaining a format which allows a small percentage of recipients to mistake it for a bill and send payment. If the amounts requested from businesses by these "solicitations" are in the hundreds or thousands of dollars, even a fraction of a percent response rate suffices for the scheme to be profitable.
Schemes involving actual fake bills or invoices (such as one where copies of a bogus dry-cleaning bill are mailed to every restaurateur in town with a "your server spilled food on my expensive suit, pay my cleaner's bill" note) have also been used to attempt to take unsuspecting victims to the cleaners.
These take a number of forms, such as the Ponzi scheme or pyramid scheme in which the addressee is invited by a "chain letter" to send money to the first of a list of names and addresses before forwarding the letter to several more people. The person starting the Ponzi scheme claims to have become rich (the infamous Dave Rhodes letter with its claim to have made $50000 is an online variant of this) but the people at the bottom of the pyramid receive nothing. In some cases, every address on the chain letter will be a drop box controlled by the person sending the letters or by one or more accomplices.
Another common get-rich-quick scheme is the Nigerian 419 scam which claims that someone wants to transfer some large amount of money out of their country (or is making a deathbed effort to donate it all to a church or charitable organisation); and all that is needed is for the recipient to send all of their bank account information and some inflated advance fee to pay for the cost of the transfer or the cost of legal counsel. Of course the massive fortune in foreign money never arrives; the scheme exists to victimise the greedy and the gullible.
The ad claims that a small fortune can be easily earned "working at home", "assembling small products in your spare time" or "stuffing envelopes" (presumably for a few dollars per piece, not the few cents that businesses actually pay to have a machine do this). Just send $29.95 for more info! Another variant claims that manufacturers are providing sample quantities of laptop computers or other high-ticket items for virtually nothing or that info can be obtained on purchasing motor vehicles for a few dollars at a secret government auction.
The info, if it ever arrives, turns out to be worthless as the easy-money opportunities do not exist as described. Most likely the only way to make money is by selling the info to another person.
A number of organizations have been set up, claiming to be charities that solicit donations to assist poor and needy families in need of financial aid, food aid and/or medical assistance. While many charitable organizations are legitimate and respected, the more unscrupulous organizations have been known to solicit large sums of money in donations, but actually contribute a very small percentage (or even none at all) to the actual persons in need of assistance.
In a similar vein, various "religious" organizations have been known to seek donations of money from well-meaning persons. These appeals for assistance often target senior citizens, mentally handicapped persons, and even homeless persons -- people who are often susceptible to pleas for mercy and compassion.
The most notorious incident of theft of mail was the Great Train Robbery, in which a gang of robbers stopped an entire mail train by tampering with railway signal lights, then robbed the train of registered mail containing valuables being sent by local banks to their head offices.