Do have a galaxy nexus mobile then you might aware of these words in title, it confuse you lot. What are these words mean? This is nothing but the firmware builds of galaxy nexus. Your galaxy nexus have android firmware one of these it depends from where you brought it from. All firmware build are comes with pure vanilla android.
These all android builds are almost same but there are some difference in terms of their android updates. And as we know all nexus device always get OTA (Over The Air) updates. eg. Samsung galaxy nexus don’t get updates via Samsung Kies desktop client. You can also manually updates the android but it’s too complicated for new users.
Too know your android build download Android System Info from Google play store.
Main Difference Between These Firmware Builds
takju : Mobiles which brought from Google play store in USA comes with takju build and it has a Google wallet pre-installed. In these device android updates pushed by Google itself and these device are almost first to receive an android updates
yakju : Mobile which brought from Google store but outside of USA, Updates are also pushed by Google, but updates might delay by some days or weeks.
yakjuxw (non-yakju) : These android build mobile devices sold by Samsung and updates are also pushed by Samsung so updates are usually delayed by couple of weeks or months.
So, do check your android build if your device is running android build other than takju or yakju (non-yakju) then change it in takju build to an android updates first.
For more info how to change android build from non-yakju to takju click here for detailed instructions.