Hamas has been lobbing an occasional small rocket into Israel, a rare few of these rockets actually hit something and a few civilians have been injured or killed. Hamas claims that these rocket firings are in response to Israels past actions, using this as a very thin justification to excuse their actions.
Israel has been bombing Gaza in retaliation to Hamas' retaliation of past Israeli retaliations. So far Israel has killed almost 500 people in Gaza, the vast majority civilians. The exchange of fire is clearly not balanced, and even the Israeli defense ministry has indicated that they do not think this action will stop the missile fire.
All this blood is being spilled for very little gain. In the end I suspect that all Israel has actually done is create a few thousand more very angry people, some of who will eventually seek to retaliate against Israel for the attacks they have had to endure over the last week.
And in reply Israel will again overreact and create a few thousand more radicals for Hamas (or Hezbollah or some other group) to use to keep their cycle of violence going.
Maybe one day someone will notice that this type of behavior has a history of limited success.