In world shops, in my opinion, are the best way to showcase your kitties. You can set them up live or in boxes and you can advertise all on your own. However with the amount of spam that we all see currently sometimes those ads go un-noticed. Not always but sometimes. I love to decorate my shop, so for me an in world shop works best. And a good point was made on the updates and kitties just sitting on the SL Marketplace for months and months. You can't see pedigrees, so you have no idea really what you are buying. Now if you are just looking for a pet to have at your house, this may work for you.
There are so many KittyCats sims it would be near impossible to "control" the market. Everyone has their favorite spot, or their favorite sim to rent and/or shop at. That is why KittyCats is a community, because we all keep it that way. Are there unscrupulous people that will try to garner sales by the old "bait and switch"? Sure there are, you will see that in any competitive arena, and breedables definitely fall into that category. It is up to the morals and integrity of the SELLER to maintain their shop and their stock. Now does real life sometimes prevent us from getting in SL, sure it does and that is understandable...heck I live at the beach and there are times when I am not in here for days in the summer. So here is where we get to the profilers.
I love them. I love being able to search the literally hundreds and hundreds of kitties to find what I want or need to continue a breeding project. There is nothing worse than walking around multiple sims for hours and not finding what you are looking for. Now for some this is a great pastime, but for me....well....I like to shop and get home LOL. So the Market Place and the profilers are a tool that I enjoy using. If I teleport to a shop and the kitty listed is not there...well heck folks that means it sold or the person, like me sometimes, has not had time to reset it. That is not the creator's fault, but real life. You have a choice at that point to look around that particular shop or sim, maybe meet some peeps, maybe share a laugh.....or go back to the Marketplace and search for a replacement. It really is your choice
MP vs Inworld shops
