Are Petitions An Effective Way of Remedying Important Issues?

I have recently been wondering about the potential effectiveness of on-line petitions, and had hoped that massive responses to such petitions could, in fact, influence policies in a meaningful way. Many of you may already be familiar with this report from Snopes on this issue, but it was news to me and I post a link to it here. The bottom line, apparently, is that online petitions are largely ineffective beyond reflecting a subset of public opinion, and are easily dismissed by policymakers and manipulated by computer techies to distort the authenticity of 'signers.' Many petitions, furthermore, are never delivered to the intended politician or group after signatures are collected. A much more effective activity for those who truly want to demonstrate their position on an issue is to write letters as a constituent to elected officials.
http://www.snopes.com/inboxer/petition/internet.asp

Big Cat News discusses the empty promise of the online petition and points out that many such petitions are used primarily to collect email addresses of individuals sympathetic to specific issues. They referred me to the Snopes piece above and also to the Capwiz site at the bottom of this post which enables citizens to write directly to their representatives on any issue they wish.
http://bigcatnews.blogspot.com/2009/01/catlawscom-and-petition-sites.html

Capwiz.com site for writing directly to elected officials.
http://capwiz.com/bigcatrescue/officials/congress/?district=08&azip=10036&state=NY&bzip=6333

Guidelines on effectively letter writing from Friends Committee on National Legislation - this is a terrific resource for people determined to have their voices recorded on the great issues of the day.
http://fcnl.org/resources/toolkit/write_congress/