Well, it seems Russia will not only refrain from retaliating to the US expelling some of its diplomats in response for the alleged Russian meddling in the US election - but Putin has also disregarded his foreign minister's recommendation to reciprocate, and will keep all US diplomats in place, and even invite their kids to the traditional New Year's festivities in the Kremlin:
http://www.mirror.co.uk/news/world-news/russia-us-35-diplomats-expelled-9536358 This is a very calculated move by Putin. Despite the fact that he is a dictator, it's also doubtless that Putin is an astute leader who can assess the situation very quickly - unlike newly elected leader Trump who seems incompetent on virtually any issue. Putin wants to show himself as the good guy here, and I think Trump will no doubt take this bait rather easily.
The problem with this sort of diplomatic "sanctions" is that there is no concrete proof of Russia participating in election meddling at a government level (although we all know they did). In the meantime, we have to keep in mind that any country (especially powerful ones) at any given time is always actively trying to hack any information they can get from another country. These hacking activities have been there for decades and will stay as long as we have the digital world. And as soon as a new medium of information transfer is invented, that one is also going to be employed for espionage.
In a nutshell, Putin has scored another point against Obama here, making him look petty at the end of his term. Of course, Putin is in the stronger position here, because he knows Obama's days in office are numbered, and he's losing the last remnants of his influence pretty fast. In other words, he's beating a dead horse. All in all, America has been trolled yet again.