Notification Strategies for Social Networks (w/ math)

http://20bits.com/articles/notification-strategies-for-social-networks/

by snakelemma • 17 years ago

36 9 17 years ago

20bits.com

andrewljohnson• 17 years ago

Very interesting and clear article.

jfarmer4• 17 years ago

Thanks!

jdrock2• 17 years ago

I'd be curious to see if Facebook and the rest use similar strategies to reduce the intra-datacenter processing and bandwidth, and if the savings achieved are worth anything significant.

jfarmer4• 17 years ago

You mean, letting the new feature go viral naturally rather than just blasting it to every person out there?

jdrock2• 17 years ago

That's part of it. I was looking at it more from a computation/energy-efficiency perspective.

bemmu• 17 years ago

What does that greedy algorithm work on, given that Facebook doesn't allow you to store a copy of the friend graph? At the point of notification, all you know is a list of user IDs that have your application, and possibly how many friends each one has.

jfarmer4• 17 years ago

Well, first, you can bend the rules. How does Facebook know whether you're storing the graph or not? They won't unless you violate the TOS in some other, more overt way.

Second, Facebook's rules say you can't store it for more than 24 hours. The current copy of the graph is available via API calls -- just call getFriends for each user with a valid session.

Third, if your app is big enough you can approximating it by seeing who sends notifications to whom, who clicks on newsfeed items, etc.

Fourth, although I used Facebook as an example, this applies to any social network with a notification mechanism. I just used Facebook because it's easier to understand -- they limit the number of notifications at the API level.

hawk• 17 years ago

one reason facebook is so viral is that it largely implements this naturally by its decomposition. that is, randomly choose seeds within a dense section of the graph (an island, or in facebook lingo, a network). it will quickly spread to the whole island, and you can grow virally island by island. this is a decent approximation under certain assumptions to an optimal centrality metric.

Notification Strategies for Social Networks (w/ math)

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