Just came across this site yesterday. So how do the options usually work? Right now I see options listed on the site. Who is selling them ? Is it other traders or is the site selling those options ?
Normally other traders, although currently I think they are quoted by "the site". Doesn't really matter for you. If you want, you can place an order in the orderbook. Or you can trade with an order that's currently in the orderbook.
The reason I asked is because it allowed me to buy infinitely many options, which other traders usually don't do. And since it is a new site, I was wondering how is that possible.
Options are traded on margin. The marketmaker currently quoting will keep quoting even if you buy out the orderbook, but then so at a slighty worse price. So yes you can buy infinitely many options (untill the market maker account has higher initial margin than equity) but at increasingly worse prices. (unlless the marketmaker actively updates prices.)
So if you want to make really a bigger trade (buying/selling 100 options), mighe be better to publish it in the trollbox to see if a deal can be made, because continuing to buy out the orderbook will soon lead to very worsening prices. This because all options are quoted by a tradebot, which is not supervised (looked at by the marketmaker) 24h/day, but adjusted several times per day by the marketmaker.