question

While it's technically possible, it's not something we would recommend. Pulling a large amount of data for a large number of users, per player, would have significant costs. To calculate this out, have a look at our pricing page: https://playfab.com/pricing/

And the meters overview: https://docs.microsoft.com/en-us/gaming/playfab/features/pricing/meters/meters

So, if you're storing posts on the player, each update of that is going to "tick" the profile write meter by 1 for every KB of that update. Similarly each read is going to "tick" the profile read meter by 1 per KB, and in both cases, that's per item read. The reads in particular are going to add up quickly, particularly for players with a lot of friends, since they'll be requesting data from a large number of other players.

While a general-purpose data system is good for a wide range of use cases (most games, for example), that's an example of a use case that requires a bespoke data backend built around very specific requirements, in order to keep costs low.

Now, that said, what we would recommend is to build on PlayFab for all the user management, monetization, LiveOps, etc. that we provide, and use a database service for your messageboard posts, so that you can design that one part for exactly what you need. Of those available (https://azure.microsoft.com/en-us/product-categories/databases/), Cosmos DB may be a good one to look at. Bear in mind that you'll want to design for privacy as a high priority, making sure to provide ways for users to be able to query for and delete all their data, per the GDPR requirements.