This is a new political term and I am not sure Wikipedia translated it entirely accurately though it made a good effort. Here is the Russian text and here it is in English. I came across the expression in a rather nasty little article on Pravda.ru [in Russian but can be translated], which was really a distasteful personal attack on various people, including the TV personality, Ksenia Sobchak, who has had the temerity to oppose Putin and his supporters. Presumably, in her case, this is seen as treachery as her father, the first democratically elected Mayor of St Petersburg, Anatoly Sobchak was instrumental in helping Putin to his present eminence and the relationship between the President-Re-elect and the Sobchak family has always been very close.
She has made videos "on YouTube parodying the spate of faux -- and often forced -- demonstrations of fealty toward the once-and-future Russian president". The name Ksyusha that is used by Putin supporters and is even in the headline of the Pravda article, is a particularly vulgar nickname with all sorts of implications for which no evidence is given. (This is a family-friendly blog, let me remind you.) The accusation in the comments to the RFE/RL video that she is merely a socialite, no more important and serious than Paris Hilton, is true enough but does not explain why there should be so much official venom directed at her.
Anatoly Sobchak was accused of various fiscal crimes though, as the Wiki piece [to be treated with some caution] points out the sums involved were insignificant in the Russia of the 1990s and less so when one looks at the wholesale theft that is going on at the moment. Nevertheless, the man fled to Paris but returned when his protegé Putin started his dizzying rise to power, campaigned for him and died suddenly in somewhat mysterious circumstances in Svetlogorsk early in 2000. (Here is an interesting account of his career without any comments about his death in the Economist.) His daughter is unlikely to gather much popular sympathy.
All that is by way of a background to the political term I read in the Pravda.ru article: внесистемная оппозиция or non-systemic opposition. The Russian Wiki, which is then duly translated (see links above) explains that in the West there are these two kinds of opposition, the non-systemic being those extreme left- and right-wing groups that fall outside the accepted norms of political behaviour. Of course, the point is that in a reasonably free society only those groups that use violence especially terrorism are defined as being outside the system. Even if they only support violence in theory they remain within the system. Otherwise we would be rid of most of our left-wing political groups and quite a number of politicians. But speech is one thing, action another.
According to Pravda.ru and this has been clear in more official pronouncements as well, however, in Russia non-systemic or, perhaps, outwith the system, opposition does not have to be violent. The white ribbon brigade, белоленточные, who may be talking of a "revolution" though mostly of a peaceful one but have not shown the slightest intention so far of being violent are seen as being an opposition outside the system, as are, presumably, those politicians like Grigory Yavlinsky, who were prevented from standing in the recent presidential election. That is rather a different definition of "non-systemic". One wonders whether anybody else will be tempted into adopting this phraseology and definition.