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Comment by gry | Hacker News Reader

His speculation on Google 160 character limit is curious. Twitter made it 140 to allow for usernames and the colon prefix. There is a real reason for it, not a sacred "140 characters is arbitrary and magical" feeling Twitter is holding on to.

http://www.140characters.com/2009/01/30/how-twitter-was-born...

Since 160 characters is/was the common limit to SMS -- which I think carriers themselves define, it feels like the author is missing a pretty key element in Twitter's implementation. The reserved 20 characters _is for_ metadata. I don't know the SMS protocol at all, but I suspect if Twitter could have dropped metadata into a header or somesuch, they would have.

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Yes, the idea that there is any extra room in the SMS protocol for metadata that Twitter is somehow missing is completely retarded.

(Source: I spent 2 years building SMS-based applications for a mobile content company. I can format my SMS in binary, and trust me, there's no space in there.)

May I ask what company/product you worked for?

I am launching my own SMS content service very soon, just curious.

They are called Boltblue (Boltblue.com). In terms of product offering they're very unexciting: just your bog-standard ringtone/wallpaper company. But I had to implement payment systems and an SMS gateway in Java, going all the way down to SMS binary format because (at the time) they sold black-and-white "service logos" for Nokias, a crazy hack which fitted 160x30 pixel binary images into multi-part SMS messages. (There are also a couple other mobile products where it's useful to be able to format your own SMS)

I learned a lot and the people who worked there were great, although it's not a company that's going places.

Most people don't use Twitter over SMS any more.

I never got that unless you followed about 4 people.

The interesting story is how mobile operators manage to charge more for sending 160bytes of data than they do for a call. And who was the genius that created the $Bn SMS business out of some spare capacity left in the GSM spec as a debugging feature.

Well, SMS is win-win from that perspective really. Sure, the 160 bytes of data costs 10 cents, which is a little crazy, but 160 characters replace a conversation that might last two minutes or more, with greetings and small-talk and such. Text is more efficient than speech for conveying information, and the social conventions around SMS make it even more so.

So consumers save money by sending a 10-cent SMS instead of making a 20-cent phone call.

I don't know where you live, but here in the states, an SMS costs 20 cents, for both the sender and the recipient, netting 40 cents for each message... It's a fucking scam that the clueless people put up with because they just don't care...

Interestingly when roaming in Europe, T-mobile charge me 40p/SMS and 20p/MMS. It is actually cheaper* for me to write down what I want to say by hand, take a photo of it, and send that than it for me to tap out an SMS!

Why is this? Well it suggests to me that they want to encourage people off the old SMS infrastructure, possibly due to capacity or manageability issues, and shift them onto the much newer GPRS/3G/whatever network.

* Yes I know you can send text by MMS and I have an E71 so typing isn't a chore anyway.

No - they know most people are going to use SMS and want to gauge them for a s much money as possible. The SMS infrastructure is fantastic (for them), they use a spare 140bytes in a message the phone is going to send to the tower as part of a 'I'm still here' message anyway - and then charge you 40p for it!

Or they could do some actual work and charge me 20p for it! Why charge less for more data? There must be a reason.

Here (Ireland) it's pretty typical for phone plans to come with all sms free, or at a low price, such as 3c a text. Even on the worst available plans you might pay 9c per sms (and only the sender pays).

I know that twitter started as an SMS app, and it may still be popular as such (I always use it on the web), but as internet-on-your-phone becomes more ubiquitous, sticking to the limitations of SMS becomes unnecessary. I'm not sure how far we are from that SMS to internet swapover, but my guess is not very far.

Respectfully, I disagree. The "SMS isn't important" argument is why Pownce failed. 50% of twitter's content is sent in via SMS. It's not consumed via SMS so much, but it sure as hell is produced that way.

And remember that the mobile Internet in the US is pretty good. In much of the rest of the world (the places where people have mobile phones but don't have computers) mobile Internet is still slow and poky. The switch-over from SMS to Internet hasn't happened even in the US yet, so it will be a long while before it becomes a good idea for Twitter to drop SMS, on the order of 5-10 years.

50% ? I'd be interested to see some data on that. Do these come up saying "from sms" rather than "Web"? If so, I've never seen one.

This pegs 'txt' as pretty darn low (3%): http://tweetstats.com/twitter_stats

Also months stats from Jan: http://dcortesi.com/2009/02/19/the-real-top-20-twitter-appli...

Wow, I stand corrected. I must have been thinking "50% of twitter is not from the web" and translating that to "50% is from txt". Apologies.

I stand by the value of SMS as a driver of valuable content, and in the developing world.

Possibly, but since it only accounts for 3% of tweets, I think they could pretty safely change the limit if they felt like it.

I know a few people who receive SMS from Twitter on their phone. I imagine there's more people receiving Twitter SMS than sending it.

More people want the option of receiving Twitter by SMS if they have to than actually do by choice day-to-day. If being out of good signal meant not being able to use the service at all, people would be less keen on incorporating it into their lives.

sticking to the limitations of SMS becomes unnecessary

I think the 140-character constraint is a huge part of Twitter's identity and success. It forces concision. It's one of those constraints that breeds creativity.

The limit is 140 octets. That can mean 160 7-bit characters, 140 8-bit (1 byte) characters, etc.

70 Unicode16 chars :) I wonder what twitter does about unicode here...

UTF is variable width; it'll use 8 bits/char if it can, and only use 16 bits if it has to.

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