> Greek's insolvency impacted Cyprus greatly, because a large portion of the Cyprus population are of Greek descent.
Just to add a little context to this. Cyprus is a divided country, as a result of a conflict in 1973 between Turkish Cypriots (and Turkey) and Greek Cypriots (and Greece). The Greek Cypriots favoured unification with Greece (Enosis) whereas the Turkish minority felt threatened by this (due to various times in which sectarian violence had spread on the Island, and also due to fears of reprisals for anti-greek pogroms in mainland Turkey). The whole thing is really complicated and basically no-one wins.
Fast forward to 2004 and a referendum is held on whether Cyprus should unify. The Turkish north votes yes, the Greek south votes no and Cyprus enters the Euro leaving Northern Cyprus out in the cold.
The people with over 100k Euros that are being affected the most aren't the Russian depositors but older Cypriots who rode the tourist property boom. There was a vote on this and it was turned down, and then the Troika (of the Eurozone countries, ECB and IMF) decided they'd sidestep the whole thing and re-arrange the country's banking system for them.
The amount the troika were looking for was not a great deal of money to the EU or IMF, about €6 billion. This represents less than the amount spent on administration or internal policies in the last budget, and would be less than a fifth of the Common Agricultural Policy (CAP) budget. This figure was also arbitrarily decided by the troika not based on what Cyprus could actually afford (given the size of it's collapsing economy) but for political reasons because it's politically unacceptable for Germany to be seen by Germans to provide no strings bailouts to another Greece, and the IMF wanted to restructure Cyprus' banking system.
The big problem is that with this intervention it sets two extremely dangerous precedents. The first is that exiting the Euro (which would've been better for Cyprus) is not an option for bankrupt Eurozone countries. It's not even on the table. The second is that what's happened in Cyprus this week can happen in Greece, Italy, Spain, Portugal, Luxembourg (where the real Russian money is) or Ireland next week or at any point in the future, and as Shenglong said, banks are the major savings depository for most of Europe. If that doesn't scare my American friends then nothing will.