How did sites like myspace and friendster grow to such a large membership?

[--]

I am working for a new professional and social networking site. We are starting our BETA launch and have lots of interest in us because we use a new invite system that no other site has. It's designed for professionals and those who travel alot so I've contacted professional organizations. Does anyone know how myspace and related sites got the word out? Did they start off with big ad campaigns or was it all word of mouth? How slowly or quickly did the membership base grow?I am not mentioning the site because I do not want to be accused of advertising.
I am really at a loss for internet marketing.

[Robert W]

I am going to guess that they grew mostly through word of mouth. That's how I discovered Myspace and Facebook--they appealed to teenagers, and then those teenagers told their friends to join, and then those friends told their friends to join, etc. It just takes awhile to get the ball rolling.

An invite system seems to be a good way to go... look at Gmail. Everybody nowadays seems to have a Gmail account, and a large part of that was through invites. Just keep offering awesome features on the web site that will keep people coming back and telling their friends.

[LaDy Qi]

It's word of mouth. The way I first got on was my friend told me about it [myspace] & i'd ask ppl if they had a myspace, & if they didn't, i'd tell them they should get one, then they'd do the same thing etc.

[husn b]

you'll find your answer on :
http://www.yamour.info
it has the greatest myspace stuff i've ever seen