Google selling unlocked Galaxy Nexus phones through Google Play is pretty cool, especially at the price they're asking. But not too long ago, that wasn't an option if you wanted a GSM Galaxy Nexus here in the states. Because of some cryptic exclusitivity deal between Google, Beelzebub, and Verizon you had to import an unlocked handset from Europe, the far east, or Canada. It was a bit more expensive, and there were some warranty concerns, but a lot of people still did it -- and most of them are still sitting on an old version of Android while Jelly Bean is available.
We're not ones to advise people to wantonly hack at their phones for no reason. That's irresponsible, and we get that most Android users love things just the way they are and don't obsess over every little thing like the more hardcore crowd does. But this is a special case. If you're in Canada or Europe, or have a phone from either place, there's a good chance you're not running the "takju" version of the OS. There's nothing wrong with what you're running, but you'll be waiting for Samsung to get around to pushing out any updates to you. Takju is the designation Google has given the build that ships on the Play Store Nexus phones, and is the one they update themselves (and first). Other variants, like yakjuxw, are more dependent on Samsung fulfilling the OTA. We want everyone with an unlocked GNex to enjoy Jelly Bean.
The simplified instructions look pretty, well, simple. Unlock your bootloader, flash the takju factory image from Google, then force the OTA to Jelly Bean. In reality, they aren't much harder. You'll need the USB cable that came with the phone, a few files, and some knowledge that you can find in the Galaxy Nexus forums about bootloader unlocking and manually flashing images. Since you're using a Nexus, it's pretty hard to break things -- but you're still going to have to follow directions. When it's all said and done, and you're running Jelly Bean on your Galaxy Nexus, you'll be glad you did it. We're sure of it. You can even relock your bootloader when you're finished, and still enjoy OTA updates straight from Google on your stock Nexus. This is something worth taking the time to do if you're an Android fan.