Estonia has become the first country to use internet voting in parliamentary elections.
Estonian Prime Minister Andrus Ansip voted online
About 30,000 used e-voting - one in 30 registered voters, exceeding official expectations.
Estonia had tested internet voting nationwide in municipal voting in October 2005, when 10,000 people cast e-ballots.
To vote on the internet, electors have to use a computer, an electronic card reader and an identity card.
E-votes can only be cast during three days of advance voting for these elections. On election day itself people have to go to polling stations and fill in a paper ballot.
E-voting systems, in which people use online machines in polling stations or register to get an e-vote password, have been tried on a smaller scale in many European countries, including in some local elections in the UK and Ireland.
But there are worries about security.
In Switzerland, where it is already an established part of local referendums, voters get their passwords to access the ballot through the post.
The Estonians say their system avoids such problems because people already have their micro-chipped ID cards and know the PIN codes to use them.
But there are still fears that an online ballot makes it far easier to influence elections.