This has actually existed for years, this is not new. You can find threads from 2009 about limited accounts on various forums. Maybe they added more limitations to these type of accounts recently though.

What features are unavailable to me? Limited users are prevented from accessing several features on Steam, including but not limited to:

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Note: CD Keys, retail purchases, and gifts do not remove limited user restrictions. See How do I gain access to these features? below for more information. Steam Support cannot remove this limited user status from your account. Why can't I access certain Steam features? We've chosen to limit access to these features as a means of protecting our customers from those who abuse Steam for purposes such as spamming and phishing. Read more... How do I gain access to these features? You will need to spend at least $5.00 USD within the Steam store. Some examples of purchases that grant access to these features are: - Adding the equivalent of $5 USD or more to your Steam Wallet - Purchasing game(s) that are equal to $5 USD or more from the Steam store - Adding a Steam Wallet card to your Steam account - Purchasing a Steam gift from the Steam store (Receiving a Steam gift from a friend doesn't count) Each Steam purchase total will be tracked in USD. If your Steam store's currency isn't in USD, it will be tracked and converted to USD automatically using daily exchange rates. What features are unavailable to me? Limited users are prevented from accessing several features on Steam, including but not limited to: - Sending friend invites - Opening group chat - Voting on Greenlight, Steam Reviews and Workshop items - Participating in the Steam Market - Posting frequently in the Steam Discussions - Gaining Steam Profile Levels and Trading Cards - Submitting content on the Steam Workshop - Posting in an item's Steam Workshop Discussions - Accessing the Steam Web API - Using browser and mobile chat What will not grant me access to the above features? The below actions will not remove limited user restrictions: - Activating a retail game on Steam - Playing free demos - Adding a non-Steam game as a shortcut - Adding/playing promotional trials like Free Weekends - Free to Play games (Examples: Alien Swarm, free versions of Portal and Team Fortress 2) - Activating promotional CD Keys from hardware or graphic card manufacturers I received my game(s) as a gift, will I gain access to all features? No, games that have been received as a gift or via Steam Trading are not eligible. What if a purchase is refunded to my bank or my purchase is disputed/chargeback? If a purchase amount is returned to your bank, the amount will be subtracted from your account's total purchase value. If the refund or dispute amount brings your account's total purchase value below $5 USD, then your account will lose access to these features. For example, if you purchase a game for $5 USD, your account will gain access to these Community features. If you open a dispute with your bank, these funds will be returned to the bank and you will lose access to these features because Steam never received the funds. What if a purchase is refunded to my Steam Wallet? Refunds credited to your Steam Wallet, such as pre-order refunds, do not modify access to these Steam Community features. What if my Steam store currency isn't in USD? If the Steam store isn't in USD, we will track the purchase amount in USD by converting each purchase total made on Steam using daily exchange rates. Once you have made the equivalent of $5.00 USD or more in total Steam purchases, you will gain access to the restricted Steam features.