Why were there so many extremely close elections in the 2000s?

[It's Perro Sanxe wot won it]

I’ve noticed that a lot of elections all over the world were decided by narrow margins during the 2000s, even by ridiculously small ones in many cases. Here are some examples:

Germany 2002: SPD beats the CDU/CSU by less than 10.000 votes, Red-Green retains a slender majority in the Bundestag.

Germany 2005: CDU/CSU emerges as the largest party by an unexpectedly close 1% margin.

Austria 2005: In a reverse of the German result, it is the SPÖ that beats the ÖVP by 1%.

Italy 2006: Romano Prodi’s center-left Olive coalition wins by 0.1%, defeating Berlusconi 49.8-49.7.

Greece 2000: PASOK obtains a narrow 1% edge over New Democracy.

United States 2000: Bush infamously carries Florida and the presidency by just 537 votes.

Hungary 2002 and 2006: 1% wins for the MSZP.

Norway 2005 and 2009: Red-Green coalition obtains slim majorities, while narrowly losing the popular vote to the opposition.

Mexico 2006: Closest presidential election in the country’s history, it is decided by less than 1%.

Taiwan 2004: Chen Shui-bian wins reelection 50.1%-49.9%

Any ideas why all these races were such nail-bitters? Is there no common root?