Why Not Do Both?

On the question of persuasion versus reinforcement in terms of political internet sites, I think it's important to remember that this is hardly a one-or-the-other distinction. Certainly, reinforcement will likely be the primary function of political websites for many years to come (at least until there is some sort of fundamental change in the way such sites function), but that hardly means the persuasion side should be dismissed.

One great thing about political websites is that even if you build one with reinforcement in mind, many of the elements that would serve to reinforce likely supporters (on-line videos, issue pages, bio, etc) can also be persuasive. If one of your reinforced supporters likes what she sees on a particular issue page and sends it to an undecided friend, that exact same element can now serve to persuade. No extra coding or resources are needed; the same element serves both sides of the equasion.

Granted, the ability of a website to persuade is dependent on undecided voters choosing to visit, but once they are there just about anything on the website could be the magic item that will persuade that particular voter. While some specifically persuadable elements could be built into the site (an 'undecided voters' section with candidate comparisons, for example), for the most part a site designed to reinforce can be perfectly capable of persuading as well.

By taking care of basic functions that can make it easy for an undecided voter to be driven towards persuasive elements ("mail to a friend" links on important pages, clear navigation, etc.), a campaign can focus on making the website as reinforcing as possible (putting most of their energy into volunteer sign-up, donations, and press), yet still retain the site's ability to persuade. Why not? It's certainly cheaper than buying another 1200 points...