The concept makes sense, but only if you hold an investment inside a TFSA that has a huge gain (it doubles in value or more).
Think of it this way: the TFSA lets you hold X dollars' worth of investments in an account that is not subject to any taxes, either while in the account or upon withdrawal. Each year, starting in 2009, the value of X increases by $5000 (and eventually larger amounts due to inflation). Thus, the total amount you can contribute to the account will be ($5000*X), where X is the number of years the account has been opened after 2009.
Since withdrawals from the current year are automatically added to the contribution room for the next year, it's possible to "boost" the value of the account beyond the $5000*X limit by withdrawing funds from any large-gaining securities. If, in 2009, you invest $5000 in your TFSA in a stock that jumps in value ten-fold, your TFSA will have a value of $50,000. You could then withdraw the entire $50,000, which would be added to next year's contribution limit. The $50,000 is permanently "locked in" to your contribution limit, and you have secured a tax shelter for life for that amount of money.
Of course, the argument is all in theory anyway, since it's very difficult to reliably find stocks that will jump in value that much in a short timeframe. It's also possible that the government would revise the TFSA rules to limit the withdrawal amounts that can be added to a future year's contribution limit.