Just to introduce the .ws domain to you in case you don't know. One company owns this domain. It's expanding its business by the referals if you are interested.
I've done some research and believe I've figured this out. My understanding is: The .ws registrar (worldsite.ws) has an affiliate link on their front page. It's a multi-level-marketing program. You pay $10 month & get a ws website. Advertise like heck and you get $1 for each referral/signup you get. It has little to do with domains. You need a credit card to sign up and need to get a referral code from the original poster.
Not really sure this is something that's going to stick! Sure the ws extension is catchy and all but nothing is really going to replace com. If there was a tld that could get anywhere close it would need massive world wide promotion and would not generated profit in the next 10 years. The only way I could see ws domain name to get anywhere close to com is if they would give the domain name totally free for the first year and generate income from hosting and renewals.