Take a look at Twitter or LinkedIn; seem like the latets fads, but they have been around for quite some time (Twitter mid 2006, LinkedIn launched May 2003).
Anyway, innovation is still happening. Here is some (getting them to work isn't always easy):
- Mjoy. Free SMS to any fixed or wireless phone. Ads will appear on the mobile portal, not in any message.
- Dial2Do. Launched April 2008 in the US and comes to 18 more countries today. Sign up, dial a 'local' number and speak. Dial2do will translate your message into an email, a Twitter message, an SMS, and more.
- Gmail voice and video chat. Goes without comment.
- YouMail. Personalised voicemail greetings, and more.
- Yotify. A little like Google alerts. Create targeted 'scouts' that'll send you hourly/daily email updates from specific sites.