I was actually thinking about petitions about private companies and their business decisions, not politics. If Tumblr or a Yahoo had their own corporate petition platform, then yes, but comparing a petition on some random website with a petition on the website of the German Bundestag is like comparing apples to orangutans.
For issues where a public petition might matter, yes. Usually they serve as social proof to press lawmakers and other public figures to deal with something. Quantifying popular opinions/demands is a powerful tool.
In this case it's just a pointless show of anger by teenagers.
