This is not true. Protesters responded with more than just rocks.
Article on how violent Egypt protest can get
Overview of protest
Protesters use #Jan25
In a post written for Hope140, @alya1989262 shared the following:
Twitter is a very important tool for protesters, as evidenced by the fact it and Facebook were repeatedly blocked in Egypt as the protests flared up. We use it to campaign and spread the word about protests/stands---hashtags are invaluable in that respect, and to share news quickly and efficiently, with our own 140-char commentary on them, and subsequently have conversations with random people/complete strangers. But most importantly, it allows us to share on the ground info like police brutality, things to watch out for, activists getting arrested, etc.