#jan25

Going back through that book of tweets from Tahrir, it looks as though the #jan25 Twitter hashtag was in use as early as January 21. It may be one of the few cases where political upheaval was successfully scheduled in advance. The reason January 25 was chosen is that it was a national holiday (Police Day, ironically) which made a large pool of protestors available in a way that would not have been the case on a normal workday.

For the same reason, there was a brief gap on January 26-27, with the strategy being to keep the streets unstable long enough for the first Friday protests on January 28. After that, things were serious enough that there was always a willing mass of protestors on any day of the week.