For service providers — especially mobile operators — short message service alternatives are worth watching, not only for the threat they pose, but also for paths they are paving for next-generation messaging.

Twitter

If any service is aiming for the sweet spot that is SMS, it's Twitter. The largely Web-based service — though you can “tweet” from your cell phone as well — has the same 160-character limit as SMS. The big difference is that while users text-message one person, a Twitter message generally goes out to everyone “following” the sender. That makes Twitter much more a group conversation medium, although it is possible to send direct messages or replies to one user.

Twitter has grown quickly; as of May, it had almost 1.8 million users, according to Compete.com. But that growth has caused problems in keeping the site running (not unlike some early SMS growing pains.)

Twitter is still mostly used by a relatively small group of tech elite, but the intensity of that usage and Twitter's ability to enable instant conversations among large groups means its growth could be explosive if it finds a path to the mainstream.

FriendFeed

The biggest challenge to Twitter comes from FriendFeed. Users of FriendFeed set up news feeds that draw in their activity around the Web, including posts at sites such as Flickr or YouTube, their own blog posts, and even their Tweets — more than 40 sites and services in all.

What has helped FriendFeed take off — and what positions it as a strong next-gen contender — is that it allows users to comment and start conversations around any post in any feed. Person-to-person and group conversations can move out of SMS, Twitter and blog comment areas and onto FriendFeed.

FriendFeed has grown even more quickly than Twitter — and without the outage pains. Its most interesting features include “lifestreaming” — building a stream of alerts covering one's entire online social life — and its ability to move conversations away from the source and onto FriendFeed. Those bear close watching by service providers.

coComment/Disqus

The ability for others to leave comments may be the real secret of blogging's success. Not surprisingly, several companies, including coComment and Disqus, are building around enabling and owning those comments.

Both services work similarly. Blog or other content site users replace existing comment systems with ones from coComment or Disqus. The services provide also provide add-ons, such as creation of profiles with all of one's comments across the Web or aggregation of comments on similar topics.

These comment services make the “message” or “conversation” the core of something bigger. They bear watching as the future of messaging evolves.