Putting your name on a list with a mouse click is a fairly empty contribution to our democracy; why would you expect anything other than a fairly empty response?
There are other ways to make things happen, but truth be the important things almost always involve a lot of energy, time, and money.
Democracy is ruling by the people. And the government has to give the people easy way to express itself. We shouldn't have to "mobilize" and "invest ourselves" heavily to change something in this new connected world. Electronic voting is one great thing, Petition through internet is another great thing if it really had an impact.
There are other ways to make things happen, but truth be the important things almost always involve a lot of energy, time, and money.