Mew’s has deleted almost all his tweets again.
Chieftan Mew’s twitter page as of the 18th of March 2012:

This might be to mark the end of the first leg of Radiohead’s 2012 Tour which wrapped up in Phoenix, Arizona on the 15th or it could be for some other reason entirely.
You can read all his deleted tweets, along with a complete record of every tweet known here. along with a annotated version of his current tweets here.
He’s also updated his Twitter Location to “Off The Grid. Into The Woods.” and his twitter display picture back to his original green one with the file name clipclopclipclop.jpg

Off the Grid is a term used for not being outside of the electrical grid either though providing your own power or simply living without it all together. While popular with people aiming for a more sustainable lifestyle it’s also a expression used for falling out of the modern world, usually with the aim of getting back to nature.
Mew’s clearly is aiming for the second as he returns to the woods, he’s used this expression before in terms of returning to the forest/woods to announce a period of silence followed by little twitter activity nor news from the band.
clipclopclipclop is a reference to the end of Episode 3 of The Most Gigantic Lying Mouth of All Time:
“What is Fear? Fear is the Clip Clop of Police Horses.
Clip clop, clip clop, clip clop.
Sleep well.”

