Hopefully I am posting this in the correct forum.
The scenario: I own a domain named (alias) "Sadly" and set it up for multiple "shop" owners to subscribe and begin selling only cars. Sadly starts to get bigger and a few shop owners sneak in and start to sell motorcycles. We cannot keep up with removing the listings and soon more shop owners sneak in and sell trailers. And so on...
The current problem: The original Sadly is not being indexed as cars only - because of the motorcycles and trailers, etc. Also the loss of the original philosophy of Sadly as a car selling site.
The proposed solution: Split up the individual sections and open separate domain names for each. The new domain names reflect the original domain, for this example Sadly1, Sadly2, Sadly3 and so on as needed (for this argument, let's say 100+ names). It's a big company!
The question: Why is this a good or bad idea? Search engines should distinguish the difference, each domain is different and a single word search "Sadly" should bring up all names first on the search page. All have the same IP address. It is proposed that each one link back to Sadly.
What am I missing? Would sub-domains be better or worse?
I promise to check in daily, a.m & p.m. US eastern. Thanks :)