CREATE TABLE table_11909 ("Model" TEXT, "Released" TEXT, "Form factor" TEXT, "Chipset" TEXT, "Memory Type" TEXT, "Max. Memory" TEXT)

Whas is the released date of the memory type ddr2-667?
SELECT "Released" FROM table_11909 WHERE "Memory Type" = 'ddr2-667'
SELECT "Released" FROM "table_11909" WHERE "Memory Type" = 'ddr2-667'