- A 20-year-old ethnic Russian man is the first person to be convicted for taking part in a "cyber war" against Estonia.
Dmitri Galushkevich was fined 17,500 kroons (£830) for an attack which blocked the website of the Reform Party of Prime Minister Andrus Ansip.
The assault, between 25 April and 4 May 2007, was one of a series by hackers on Estonian institutions and businesses.
At the time, Estonia accused the Russian government of orchestrating the attacks. Moscow denied any involvement.
Kremlin spokesman Dmitry Peskov told the BBC in May 2007 that the allegations were "completely untrue".
The attacks took place against a backdrop of riots by ethnic Russian Estonians prompted by the removal of a Soviet war memorial from the centre of Tallinn.
During the unrest, one person was killed and more than 150 injured.
Moving the so-called Bronze Soldier was seen as an affront to the memory of Russian soldiers who died during World War II.
Prosecutors said Mr Galushkevich, a student, had claimed the attack was an act of protest against Mr Ansip, who became a hate figure for Estonia's Russian minority.
Ethnic Russians make up about a quarter of Estonia's population of 1.3 million.