Google’s One Number does a lot of things, and does them well. Its core utility, actually, is being able to take care of a lot of things, namely a lot of phones. You give out your Google Voice number instead of any other numbers you may have – such as a home phone, a personal mobile or a work cell. When someone calls the One Number, it gets patched through Google’s servers where your own filters are applied – depending on who’s calling it will be directed to home or work or simply voicemail, where the message can be transcribed and sent to your email for free.
This is awesome for anyone who hasn’t been using the same phone number for many years. But when literally hundreds of people are used to finding you at a certain number, suddenly changing to Google Voice seems less of an option.
Google has solved that one as well, allowing you to now make an already existing phone number your One Number. But it requires a bit of an awkward and fuzzy switch from one contract to another, and a $20 fee paid to Google. But once you’re done with the process, you have a fully functional Voice account, and your old number’s still there.