[erlang-questions] Twoorl: an open source Twitter clone

Per Melin <>
Fri May 30 17:02:03 CEST 2008

2008/5/30 Joe Armstrong <>:
>  - what is Twitter?

It was launched as a "micro-blogging" service. Each post is limited to
140 characters (like an SMS).

Users can follow what others post with RSS, SMS, instant messaging,
desktop applications (through an API), email or on the Twitter

Some users have tens of thousands of "followers" and some follow
thousands of people.

>  - the reaction to your work seems to be (oh but it doesn't  scale -
> so Erlang must be no good -
>    despite the fact that I believe you expressly said it was a quick
> hack and wasn't designed to
>   scale)

I think the reason for this is because Twitter is plagued with daily
outages because they can't handle the load, and the internets have
been filled with speculation on why this is, and how these problems
could be avoided. In these discussions you can often find a commenter
saying that they would've used Erlang and that would've solved all
problems more or less automagically.

>   So what does it do? How many things must it scale to (give me
> numbers here - what are
> talking about - scaling is not some abstract quantity - it's number of
> bytes of data delivered to end-users
> per gram of CO2 - how many bytes/gm of CO2 are we aiming at?)

In March Twitter had on average 200 000 users per week with 3 million
messages sent per day.

They have raised $20 million in venture capital to a $100 million
valuation. So they can afford to buy hardware.

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