A law passed to appease the church that will be selectively employed against any potential opposition. Doubt they'll be burning Pushkin's books any time soon.
edit: the CNN article makes it sound like swearing in general is banned, which is incorrect. In Russia there is a slang called mat which is a sort of prison/street slang. It's complex as slang tends to be, but essentially what's banned is four words (and their derivatives): khuy (“cock”), pizda (“cunt”), ebat’ (“to fuck”), and blyad (“whore”). Mat was banned in Soviet times as well. Lots of writers now considered greats have used mat.