Yeah, interested
I am heavily involved with the Steam marketplace, most notably CS:GO.
Really depends on the pricing and the features that come with it. Going to watch this thread
The only thing I'd be worried about as a site operator for something similar to this is the banning of the trade bots. Not because it's illegal in any way, the steam auto trade bots are used everywhere including sites like CSGOLounge, but there have been stories (recently) where these bots, holding fraudulently obtained items would get banned. Other times, the bots may get mass reported by trolls/scammers and then also ends up getting banned.
Most recently, a site called CSGOJackpot had their trade bots trade banned with a total of about $500k worth of skins locked on their bots, untradeable.
Obviously there isn't much the site owner can do when Valve decides to issue bans, even legitimate users have been getting banned recently because valve's anti fraud system is just flawed. But I just thought I'd point that out to anyone who may be interested in starting a site that utilizes steam bots for automation.
1. System won't keep items on it's bots. We have 4 hours "guaranteed" storage of item on our trade bot after success deal(mean, after you sended money and trade bot sended you trade offer). If you want to sell something, you need to be online, bot send you trade offer for choosed item and you must give it to bot. In that case, we minimize risks of bot banning with full of items on it)))
2. Bot banning is real headache(yeah, it's just trolling guys, who report trade offer as a scam), but, i'm going to create special system to easy add bot at admin panel and pass first-time-launch steam guard and other shit.