Andy's right. I've also heard it referred to as the "seat of the pants" rule. If you can make the transfer without getting up off the seat of your pants, it probably counts toward the limit of 6. (Examples: telephone transfers, automatic transfers, online banking transfers.) If, on the other hand, you exert some energy to get up and go to the ATM, or go in person, or arrange for a messenger, it will not count.
I think it helps to think about what they're trying to accomplish through this rather crazy-sounding scheme. The intent of Congress and the FRB is for financial institutions to be able to attract deposits on which they will not have to pay interest. In order to do so, they have placed various restrictions on interest-bearing accounts, to make them less attractive. NOW accounts have strict eligibility limits. CDs have early withdrawal penalties. Savings deposits and MMDAs have limits on transfers/withdrawals. The delineation of what counts as a covered transfer or withdrawal represents a kind of a balance. They didn't want to bring all transfers/withdrawals under the umbrella because that would create accounts that would be too inflexible to be attractive to most customers. On the other hand, if they allowed unlimited transfers/withdrawals, money would flow out of noninterest-bearing accounts immediately and everyone would want only accounts which paid interest.