This community's favorite thing is to complain about something that's ill defined. A post about BGP without saying it's the border gateway protocol will have its comments go off on a stupid tangent of if an HN reader should be expected to know what BGP is. (seriously people, go Google the term and don't demand everyone spoon-feed your intellectual midgetry!) Thus, an explanation that Yandex is Russian Google is to try and head off that derail. Of course, now we're having this discussion instead, so it seems like we can't win.
Even if I've heard the name Yandex before, it's a good reminder of what it is.