Red shirts. Yellow shirts. Blue Shirts. Pink Shirts. White Shirts. Orange Shirts. Purple Shirts. Black Shirts. Be careful what you wear in Thailand today. Your politics are determined by the color of your shirt. A blogger suggests that tourists should wear floral shirts in Thailand in order not to be identified with any of the political forces here.
The two main conflicting groups are the Yellow Shirts and Red Shirts. The Yellow Shirts belong to the People’s Alliance for Democracy . The Red Shirts are supporters of the United Front for Democracy against Dictatorship. The Yellow Shirts are consistent critics of former Prime Minister Thaksin Shinawatra  who was ousted from power in the 2006 coup. Most of the Red Shirts are supporters of Thaksin.
The Yellow Shirts adopted the color yellow as their protest color in honor of King Bhumibol Adulyadej, the most revered figure in Thailand today. But it doesn’t mean the Red Shirts are opposed to the King. It also doesn’t mean that they are leftists. They adopted the color red just to differentiate themselves from the Yellow Shirts.
The Yellow Shirts accused two Prime Ministers last year of being puppets of Thaksin. To force change in government, the Yellow Shirts organized provocative street actions  last August. They occupied the Government House for several months. They shut down Bangkok airports  last December which crippled travel in the country. The Yellow Shirts agreed to end their protests when a court order  disqualified allies of Thaksin from running for public office again. (See Global Voices special page on the protests  initiated by the Yellow Shirts).
A few days after the Yellow Shirts declared victory, the Red Shirts began to organize  their own street actions. They also occupied the Government House a few weeks ago. They were able to gather tens of thousands  of protesters in Bangkok. They were supported by taxi drivers  who used their cars to block traffic in Victory Monument, a busy intersection in Bangkok. The Red Shirts succeeded in forcing the cancellation of the ASEAN Summit  in Pattaya which embarrassed incumbent Prime Minister Abhisit Vejjajiva. There is now a state of emergency in Bangkok, but the Red Shirts are defiant .
Jonny Foreigner notes the similarity of Yellow and Red Shirts :
The Yellow Shirts got what they wanted by causing chaos and closing the national airport so the Reds (significantly made up of a strong presence outside of Bangkok) took this marker and went for the heart of the capital – closing roads and massively inconveniencing the city.
Who are the Red Shirts? What do they want? The Yellow Shirts describe them as ignorant followers of Thaksin. Siam Report read a report which disputes this stereotype :
There are also reports coming out that many Red Shirts are individually well-off, driving their own cars and living in and around the capital. Their demands are for a real democracy and a rooting out of the unelected elements that frequently interfere with the political process. However, they are not interested in a return of Thaksin and do not swear allegiance to him. The Red Shirts can no longer be abused and ridiculed as a monolith of “poor uneducated Thaksin stooges”, as was previously the norm in certain media quarters.
The Yellow Shirts are not active today. But the Red Shirts are being confronted by a different set of “colored” protesters: The Blue Shirts.
The Blue Shirts emerged when the Red Shirts began to mount a serious challenge to the government. First, they said they only wanted to protect public utilities , like the airport. But the Red Shirts soon accused them as being thugs hired by the government. Nirmal Ghosh writes about the confrontation between the Blue Shirts and Red Shirts  which may shed light about the real leaders of the Blue Shirts.
In the early morning they (Red Shirts) began marching up the hill to the Royal Cliff Resort, venue of the summit, but came face to face with a few hundred of the pro-government militia, well organized with freshly printed dark blue T-shirts saying ‘Protect the Institution’ – institution being the a reference to the monarchy.
All the blue shirts were armed with sticks, clubs and iron rods.
The face-offs occurred at two locations, each with around 1,000 red shirts against about 150 blue shirts. The men in blue held pictures of the king and queen.
The blue shirted men – clearly a militia – essentially took shelter behind the army, whose officers made no attempt to disarm them.
According to two sources, the blue shirts had been organized by the mayor of Pattaya, who is the son of ‘Kamnan Poh’ – a controversial strongman of the province.
What are the reactions of Thai residents who are not directly involved in the political crisis? When the Red Shirts were leaving the ASEAN Summit venue in Pattaya, a group of people wearing black shirts  began throwing stones at them. Who are they?
Some are confronting the protesters. Check this video on how some Red Shirts were driven away by angry pedestrians:
Perhaps the decision of many Thais to wear “neutral” colors can be interpreted as a political statement too. Via Twitter, the other “colored” shirts in Thailand:
sajal : no.. youll get thrashed from both sides… RT @jamiemonk: I am wearing orange shirts from now on.
stickmanbkk : Red shirts, yellow shirts. Im wearing my white shirt!
thaicam : a friend opines: Maybe it's time to combine Red+Yellow and create Purple Shirts who actually rally for the country, not their own ideology.
bangkokpastor : Yellow shirts, red shirts and now blue shirts? before long there will be no way to dress neutral.
Tbarrett : I'm anxious about tomorrow's demonstrations here in Bangkok. Red Shirts! Yellow Shirts! Who's gonna win the Biggest Dumbass award?
gregkjorgensen : Funny how red AND yellow shirts scream for democracy, but are unwilling to accept the results of an election if it doesn't go their way.
PT789 : Last time it was the Yellow shirts taking over the city, now it is the red shirts… when will they stop playing this ‘political ping-pong’
There is another option for Thais: wear pink. The Pink Shirts want a political formation based on love. Pop singer Jintara has a music video for the song ‘Mop see chom-poo’ which preaches the doctrine of the Pink Shirts.
Shameless Mack advises tourists to wear only floral shirts  in Thailand
Indeed, the situation is becoming more and more unpredictable. The red shirts are able to move their forces from place to place. While the yellow shirts – the ones who closed the airport last November/December – have not yet re-appeared, the emergence of the blue shirts cannot bode well. It is even more troubling that on their very first appearance, the blue shirts provoked violence.
One more thing: Do not go out on the streets wearing solid-colour T-shirts. Yellow and red already indicate political affinity, and now dark blue is another group. Who knows what new colours may become too “hot” to wear tomorrow.
What to do? Pack only floral shirts.
Thumbnail image used from the Flickr page of Y-Not