Key Content Attributes & Details
First, a key area that marketplace eCommerce owners need to consider is acquiring content. This can be a helpful starting place, but ideally would not be something that's the primary source long-term. There are many databases of products available that have standardized product information and depending on the industry that you're in this might be a valuable starting place to get baseline content and product details, descriptions, meta information, and imagery.
These resources are generally available to other competitors in the industry, meaning it’s not unique content. That may not be a huge issue if organic SEO and other forms of unique content aren't a primary concern in the long term, but it is a consideration that any business will want to make sure they factor in.
One of the things that can be helpful with off-the-shelf content comes from product and catalog data sources as they can give a good baseline of categories that are standard within your industry. They can give you a good baseline for how products could be built out with their descriptions, titles, and meta information such as SEO titles, page titles that get indexed by search engines, URLs, alternate tags for images headlines, etc.
These are all things that you can get a value from even if you don't permanently use that content. You can temporarily use it to be a placeholder. Eventually, they can then be updated by your internal team or, better yet, many of your marketplace site owners will enable users to upload content as a vendor.
Over time, this will make the content unique within the site itself allowing the vendors to quickly find things and standardize the content. Administrators can update and extend the content to make it unique to the marketplace itself.
Look at it as though you're getting a one story house and small foundation to start with, but overtime you are extending the foundation and adding more stories, levels, and rooms to the house just by consistently growing and extending the content on the site.