Passing the 100,000 mark means that under the White House's own rules, the administration has to respond to the e-petition in a timely manner.
If you are a reasonable adult human, your instinct is probably to roll your eyes at this news. Which, sure, I don't blame you. We're already all set for Bieber news, and no one really thinks Bieber will be deported (particularly not because of an e-petition). But the Bieber e-petition reminds me of another petition that I wasn't wild about, the e-petition for the White House to build a Death Star. It's essentially the same premise -- hijacking a tool that's supposedly built for Important Democratic Expression and using it instead for silly internet jokes.
Except what I learned from the Death Star e-petition is that jokey e-petitions these are actually kind of good for the system. First, because they act as infomercials for the e-petition system itself. Many more people will learn it exists because of this silly story. Secondly, because when people see that the White House does, in fact, stick by their own rules and respond to even the most outlandish petitions, it gives them faith that more serious petitions will also get some kind of response.
Lastly, it's worth remembering that while the White House doesn't have to take action beyond acknowledgment of a popular e-petition, they have done so a few times in the past.