This excerpt taken from the IWOV DEF 14A filed Apr 29, 2008.
Restricted Stock Units
In general, no taxable income is realized upon the grant of a restricted stock unit award. The participant will generally include in ordinary income the fair market value of the award of stock at the time shares of stock are delivered to the participant or at the time the restricted stock unit vests. Interwoven generally will be entitled to a tax deduction at the time and in the amount that the participant recognizes ordinary income.