Techcrunch:

To understand neutrality, you have to understand an esoteric concept called “common carriage.” Since 1934 and the advent of common carriage in the U.S., telephone service providers have been prohibited from deciding who you can call or what you’re allowed to say while you’re talking. We take this freedom for granted in our voice communications. But for SMS, where messages aren’t afforded common carriage, carriers are responsible for policing the content of the communications.

Since 2010, innovators have used the power of communications by leveraging open access to SMS to deliver new products and services to consumers. In that time, companies such as Uber, Lyft, Airbnb, Nordstrom and The Home Depot have delivered customer experiences via the ubiquitous mobile medium of SMS.

But unfortunately — due to the lack of network neutrality rules — we’ve seen carriers block messages from customers for arbitrary and unpredictable reasons – for example, because they contain web links, because they reference alcohol, and because — and I’m not making this up — they reference content from Urban Dictionary. Do we really want an Internet where carriers police the content that we see? Should we really choose between a Fox News Internet and an MSNBC Internet?

Imagine if voice calls operated this way and your carrier could decide if you could receive a call from your bank, your grandma or your doctor based on whether they’re on some carrier-approved list. Seriously, imagine that. Zero people, probably even the carriers themselves, would support that plan. Yet it is exactly what happens with SMS, and it’s assumed that’s just how it is. This situation exists because SMS is not afforded common carriage protection like voice is.

A very interesting observation.  There is no doubt that SMS has not flowered in the way the web has.  I was always puzzled why a Telco didn’t compete with Twitter.

This related article gives a more details.