The biggest contributor to the slow adoption in the mainstream has been the absence of a universally distributed RSS "reader" on every computer (similar to how Outlook or Outlook Express on every Windows PC helped make email universally understood). But that should also change shortly as more RSS readers get included in Web browsers and email programs in the near future.
So while the "big guys" will push their messages to consumers by paying what will surely amount to an ever- increasing "toll" to get their emails through email list, the "little guys" will "pull" consumers to them with subscriptions to blogs and RSS feeds.
Whether it happens this year, next year, or the year after - make no mistake - the email "toll booth" is coming for commercial emailers and newsletter publishers. So, if you depend on sending email for your company's profits, either get ready, plan, and budget for the new tolls, or start making arrangements to distribute your content via blogs and RSS feeds, because the market will shortly force you to make a choice. As the internet is flooded with aspiring online home-based entrepreneurs and marketers, web consumers are constantly receiving their emails promoting their brands and wares.