IPFS stands for "Interplanetary File System", and it is a distributed system for storing files, similar to Bittorrent and most peer to peer file systems.

From the IPFS page at Wikipedia:

IPFS allows users to host and receive content in a manner similar to BitTorrent. As opposed to a centrally located server, IPFS is built around a decentralized system of user-operators who hold a portion of the overall data, creating a resilient system of file storage and sharing. Any user in the network can serve a file by its content address, and other peers in the network can find and request that content from any node who has it using a distributed hash table (DHT).

In contrast to BitTorrent, IPFS aims to create a single global network. This means that if Alice and Bob publish a block of data with the same hash, the peers downloading the content from Alice will exchange data with the ones downloading it from Bob.[6] IPFS aims to replace protocols used for static webpage delivery by using gateways which are accessible with HTTP. Users may choose not to install an IPFS client on their device and instead use a public gateway. A list of these gateways is maintained on the IPFS GitHub page.

Source: https://en.wikipedia.org/wiki/InterPlanetary_File_System

At Libra.Codes, we use IPFS to push the files uploaded by our NFT creators for several reasons, including:

• IPFS is the chosen standard to keep tokenized files in the cloud.
• Files in IPFS can't be changed.
• We can have multiple IPFS servers to suit our system needs without scalability issues.

When you purchase an NFT on our marketplace or the auctions center, it is very important to download and backup the file for the next reason:

Our IPFS servers keep all files "pinned" so they aren't deleted.

When someone takes an NFT out of our system, the file keeps pinned for at least a month. Once this period concludes, the file might eventually disappear from IPFS unless the new owner uses a third party pinning service like Pinata to keep the file alive in the IPFS network.

That being said, tokens with multiple copies are kept in IPFS until the last copy is sold out and withdrawn. Still, the best practice here is to download your acquisitions as soon as you get them.