The Jamestown Foundation's Eurasia Monitor, 12 Oct 07:

ECHR Ruling Highlights Discrimination Suffered by Turkey's Alevi Minority
The October 9 ruling by the European Court of Human Rights (ECHR), stating that compulsory religious instruction in Turkey violates the rights of religious minorities, has highlighted the discrimination suffered by the country’s substantial Alevi community (Aksam, Milliyet, Radikal, October 10)....

....Alevis have traditionally been regarded with suspicion by Turkey’s Sunni Muslim majority and suffered both discrimination and occasional pogroms. In July 1993 37 people were killed when a Sunni Muslim mob set fire to a hotel in the Anatolian city of Sivas that was hosting an Alevi cultural festival. Although it fielded a few token Alevi candidates in the July 22 general election, Turkey’s ruling Justice and Development Party (AKP) is an almost exclusively Sunni Muslim . Both publicly and privately, leading AKP members have frequently refused to recognize Alevism as a distinct religious tradition, regarding Alevis as renegade Sunnis rather than having an identity in their own right. In September 2005, Prime Minister Recep Tayyip Erdogan publicly dismissed Alevism as a culture rather than a religion and said that the only place for prayer was a mosque.....
My wife is an Alevi Kurd from the eastern part of Sivas province in Turkey (right up against the border with Erzincan province, for those who care about such matters). We actually stayed at that very hotel in Sivas not a week prior to the incident.

The article actually puts it pretty mildly. Among many Sunni Turks there is a real depth of prejudice and bigotry against those who are known to be Alevis in Turkey, and many nasty myths spread around about them in the country. The one that really angers the Alevis is the one about "mum söndü" (the candle went out) - Some Sunni Turks like to relate that the Alevi have a ceremony where they gather together in the evening, they put out the candles, and then engage in incestuous and adulterous orgies. In the culture, this goes beyond being an extreme insult, the tale debasing Alevi family and personal honor.