Along the same theme. Some related stories.

When my sister got a cell phone, their last four digits were matched to their home phone. That makes it easier to learn both.

Many people at my work-place do not know the work number. Its the simple reason that its programmed in phones, and they never needed to learn it.

The fact VOIPo gives a list of numbers to choose from is more than Vonage offers for comparison.

The a-la-cart 1-877 I have with another company was obtained for an extra $15 fee. The last seven digits match my wife's cell phone. The research used an AT&T site (I think?) but the manual request just specified that number and took some time.