NIAC is confused:
Earlier in the day, we saw a message posted on Mousavi’s facebook page saying “Mousavi & Karoubi ask supporters NOT to attend Friday prayers (which is being delivered by supreme leader Ayatollah Khamenei).” We thought this was strange, since they were saying exactly the opposite just a little while ago. Now, Nico and the NYT both have commented about the same message going up on Twitter. Just as we were trying to figure out what was going on on Mousavi’s facebook page, the message was removed. This appears to be an organized attack on Mousavi and Karroubi’s facebook and twitter accounts to send misleading messages to supporters. We got the impression that they were trying to take these messages down as fast as possible, so we are pretty convinced they’re not legitimate.
I think I have a better handle on what's going on. It seems as if a) the supposed Mousavi "request" for people not to attend prayers is a hoax, but b) Mousavi has decided to delay a planned Friday rally until Saturday.
The Dish 