You're right. Just because everyone uses it, doesn't mean it's "good". By making most ads free, Craigslist dominates the market even though they have a poor product. Take these examples:
- Buy a car. Poor make/model/year metadata requires loose searches to identify cars with keywords. So you end up sorting through irrelevant cars, or missing out on the ones you want to see.
- Find an apartment. Map search was finally introduced after Padmapper did it. Before then, you could search by the names of neighborhoods, but then you'd have the same problem: sort through tons of mis-categorized results, or miss out on the apartments you wanted to see.
- Buy used electronics. Again, poor category metadata. Want to buy a MacBook Pro, or iPhone 7? Good luck manually sorting through results that include the word "retina" or "non-retina" - or similar issues.
- Advertise your business. Great news, ads are free! Bad news: the flagging system is terribly abused, and there's no recourse because "it's free" and "the community does the flagging".
In all these cases, whether I'm the buyer or the seller, I'd much rather pay a small transaction fee or advertising fee for a better marketplace. But usually, craigslist dominates. They don't dominate because the product is good, they dominate because of network effects and an artificially low (free) price for most listing categories.
- Buy a car. Poor make/model/year metadata requires loose searches to identify cars with keywords. So you end up sorting through irrelevant cars, or missing out on the ones you want to see.
- Find an apartment. Map search was finally introduced after Padmapper did it. Before then, you could search by the names of neighborhoods, but then you'd have the same problem: sort through tons of mis-categorized results, or miss out on the apartments you wanted to see.
- Buy used electronics. Again, poor category metadata. Want to buy a MacBook Pro, or iPhone 7? Good luck manually sorting through results that include the word "retina" or "non-retina" - or similar issues.
- Advertise your business. Great news, ads are free! Bad news: the flagging system is terribly abused, and there's no recourse because "it's free" and "the community does the flagging".
In all these cases, whether I'm the buyer or the seller, I'd much rather pay a small transaction fee or advertising fee for a better marketplace. But usually, craigslist dominates. They don't dominate because the product is good, they dominate because of network effects and an artificially low (free) price for most listing categories.