This is old news (July of this year) but I didn’t see this post until now. Tom from MySpace explains what the idea was behind the phrase “extended network” on MySpace, and why they eventually got rid of it.

if dave knows john and john knows amy, then dave could see amy in the network. when you’d view someone’s profile it’d show if you were friends, or how you were connected to a person … within a week (or maybe even less time, hard to remember), we realized that this ‘network’ concept was really hard to scale .. the site was slowing down trying to process this relationship each time you viewed a profile. in fact, i later heard from a friendster developer that this is what slowed them down for the first year.

I thought it was pretty interesting, especially when he goes on to explain that people preferred simpler controls anyhow (public, private, friends only) and didn’t see the value in the “extended network” concept. This is in obvious contrast to LinkedIn, where the degrees of separation are an important aspect of the site (obviously, the sites serve different purposes). My gut feel is that it wouldn’t be hard to get that to scale (memcached hashtable with extended friend ids?) although MySpace’s userbase is roughly ten times larger than LinkedIn’s.