First and foremost, your Gift Box now has two different limits. Whereas before, the limit was technically 500 items (granted, there were plenty of ways to go above that, but we won't go there), now, the overall limit is 5,000 items. That's for total items, regardless of duplicates, meaning that you could have 1,000 Special Delivery Boxes, 1,000 Fertilize Alls, etc., until you reached the 5,000 item limit total.
As for the other limit, this comes in how many total unique items you have. This limit is 500. To give this one an example, you could have 500 different items, only having one of each, in your Gift Box before being unable to technically accept more. You could have one Red Calf, one Special Delivery Box, one Cow, one tree, and so on. The second you added a duplicate item to the list (say, two trees instead of one), you will then only be able to hold 499 other unique items. Of course, the possibility that someone would ever reach 500 unique items before clearing it out is pretty far fetched, but I digress.
Overall, this means that your new gift box works on a "whichever limit is reached first" system, and it will start to delete items (or whole groups of items) if the limits are crossed, based on rarity. If you happen to have 1,000 Mystery Seedlings in your inventory, for instance, along with 499 unique, rare items (Fuel, Love Potions, Instant Grows), you will have reached your 500 unique item limit. As the game judges your Gift Box based on item rarity or value, these Mystery Seedlings are at the very bottom of the list. If someone then gave you an Unwither Ring, which is arguably the most rare item of all, all 1,000 of your Mystery Seedlings would be deleted, simply to give the Unwither Ring a slot in your Gift Box.
Here's an example list of item rarity, starting with the least rare and going to the most rare, straight from the game's official forums:
Gift-able items, coin price items (SDBs, seedlings, watering cans)
Non-consumable, non-LE coin items (haybales, fences)
LE coin items (themed coin decorations)
Consumable LE items (Captiol One Quick Grow) WILL NEVER BE DELETED
Non-consumable cash items (Unwither Ring, Platinum Mastery Statue) WILL NEVER BE DELETED
Consumable cash items (Fuel, Love potions) WILL NEVER BE DELETED
As you can see, there are whole groups of items that can never and will never be deleted from your Gift Box, regardless of how many times you breach the 500 / 5,000 total item limit(s). However, those items in the first three categories are fair game, so make sure to periodically clear out your Gift Box, just like you probably do now, to save yourself from losing all of those freebies.
What do you think of these new Gift Box item limits? Do you think they're fair, or should Zynga simply make the cap unlimited and be done with it? Sound off in the comments.