A petition, to me, represents two things. First, it gives a rather vague idea of the stand of the population on a particular issue. For example, the petition for the stepping down of former NKF CEO showed the significant displeasure of Singaporeans on that issue. Most of the time, a petition sheds little light on this (simply because the signature collected are not overwhelming enough to deliver a message), but sometimes it does work.
That, of course, is the pragmatic perspective of a petition. Down to a personal and more idealistic view, a petition shows one's stand a particular issue. Specifically, and especially when one does not sign a petition anonymously, it goes to show the committed stand made by that individual. It is certainly more than a stand made in one's mind, because when one chooses a stand before the public, it requires a greater commitment than an internal one.
That being said, with regards to
the Repeal 377A petition, I doubt it will help shed light on the pragmatic front, but at least I do think it is a good chance for me to state my stand. Thus if you have a stand committed enough on this issue, please consider this petition.