In the United States, Karl Hess used bartering to make it harder for the IRS to seize his wages and as a form of tax resistance. Hess explained how he turned to barter in an op-ed for The New York Times in 1975. However the IRS now requires barter exchanges to be reported as per the Tax Equity and Fiscal Responsibility Act of 1982. Barter exchanges are considered taxable revenue by the IRS and must be reported on a 1099-B form. According to the IRS, "The fair market value of goods and services exchanged must be included in the income of both parties."
Make the deal. After you've found a barter partner, get the agreement in writing. Make sure you detail what services or goods will be involved, the date of the exchange (or work to be done) and any recourse if either party reneges on their part of the deal. If you are working through a membership-based bartering association, they will likely provide all the structure and paperwork you need for the deal.
In Canada, barter continues to thrive. The largest b2b barter exchange is Tradebank, founded in 1987. P2P bartering has seen a renaissance in major Canadian cities through Bunz - built as a network of Facebook groups that went on to become a stand-alone bartering based app in January 2016. Within the first year, Bunz accumulated over 75,000 users in over 200 cities worldwide.
Other countries though do not have the reporting requirement that the U.S. does concerning proceeds from barter transactions, but taxation is handled the same way as a cash transaction. If one barters for a profit, one pays the appropriate tax; if one generates a loss in the transaction, they have a loss. Bartering for business is also taxed accordingly as business income or business expense. Many barter exchanges require that one register as a business.