Is the Bitcoin blockchain being exploited, causing major congestion?

Scalability has been on my mind a lot lately, and I keep wondering about it. As someone who's not a pro but wants to learn more about Bitcoin's technical side, I've been asking questions to get insights from those who know better. I brought up a topic a couple of days ago about scalability and how we can tackle the congestion and high transaction fees we sometimes face. I got a bunch of opinions that seemed pretty expert-driven, but I'm still not satisfied. Maybe I should just set aside the scalability topic for now and explore other areas, or maybe I should dig deeper to find clear answers to understand it better. One reply I got was pretty straightforward and easy to follow, even for a newcomer. The writer confidently pointed out that spam attacks are a significant contributor to congestion (please correct me if I got that wrong). Also, the introduction of Bitcoin Runes, Ordinals, and BRC-20 tokens has stirred up speculation about them being potential spam sources on the Blockchain. Ordinals, known as Bitcoin NFTs, let people inscribe images, text, and more onto the Blockchain. BRC-20 is an experimental token standard for minting and transferring tokens using the Ordinals protocol, while Runes is another standard designed for creating fungible tokens.

Obviously it is. Bitcoin developers allows it and they should know what they will do about it. If another huge buying comes, they will also still add to the blockchain congestion. We should have lower fee rate by now. So they are even a problem now. Only bitcoin developers are the ones that can make this discussion and it is clear that they want the tokens to stay. Yes.

OP, a lot has been written already about this issue in several threads. Most were however more active in 2023 and early 2024 when the Ordinals wave was at is maximum, when I think you weren't still around in this forum. I'll try to briefly summarize my opinion about these topics in simple terms: There are two problems with Ordinals/Runes. The first one is the presence of transactions with big amounts of data (up to 4 MB in some cases). This is actually the  "exploit" some talk about, because a Taproot "feature" was mis-used to circunvent limits for standard data transactions and thus storing lots of data in a transaction became cheaper. However, these transactions have only led to mempool congestion for a brief time in early 2023. The second problem has much more incidence in the congestion: the appearance of tokens like BRC-20 and, more recently, Runes. These transactions are small, but their purpose isn't to transfer Bitcoins so they can be seen as "spam" by those wanting to limit the Bitcoin network for "payment" transactions. However, tokens on Bitcoin are nothing new. They exist since 2013 approximately (coloured coins, Omni/mastercoin). And more important: with the Bitcoin protocol it can't be prevented that such tokens are created (early token transactions looked exactly like normal transactions but had the data embedded in sequence fields and fake public keys). I believe we will see some waves still, more from Runes than from Ordinals, but they will become much less pronounced. BRC-20 is already almost dying. Runes transactions have seen a second wave now but it's lower than the first wave (near the Halving event in April). Neither of both. We should support all investigation which goes into second layers (which is the "transaction batching" aspect some mentioned in your other thread). This is not a fact like the answer to 1, but a personal opinion. I'm generally in the "small blocker" camp. If you think every data transaction is an "exploit", then probably yes. Data transactions like Ordinals, Runes, and to a lesser extent older protocols like Counterparty, Omni etc. are making up around 50% of the block size currently. But if you only take into account the Ordinals which used the exploit I mentioned above, then its incidence is low, as I mentioned before. Disagree. They are quite neutral about them, but an aggressive development action against OP_RETURN tokens like Runes could cause massive side effects like a bigger UTXO set due to "fake public key tokens" like Stampchain.

I hadn't joined at that time. I saw the need to ask questions so I could catch up with many things that I have missed so far. I guess this might be the last question based on this matter.

FYI, almost or all who reply aren't from expert. By expert, i mean someone who get paid as blockchain or Bitcoin developer or known for major contributing on Bitcoin protocol or software which utilize Bitcoin. 1. Short answer, yes. But IMO using OP_RETURN is tricky to be considered as exploit when it's created to store aribtiray data. Meanwhile, i consider usage of witness data, signature (on multi-sig address) and similar stuff as exploit. 2. Probably yes. I expect someone will try to rebrand those as "new" or "unique" innovation. 3. Yes. Who wants to see block size got increase only to be filled with Ordinals or other TX which aims to store arbitrary data? 4. Yes, i've seen some chart which shows majority of block filled with Ordinals (or similar ones) for some time.

Then you may like to see some history about spam attacks as well. I tried to list some cases in this topic a couple of years ago: https://bitcointalk.org/index.php?topic=1776143.0 We've been dealing with different types of spam attacks for a long time. I consider Ordinals to be the continuation of the same attacked called "stress test" back in 2015 but much more severe as it get regular users to participate in the attack without knowing they are actually performing an attack. All the prolonged and major mempool congestions so far have been due to spam attacks. This should have been nipped in the bud. At its very early stages when the scam market hadn't grown, introduction of standard rules could have had a high chance of preventing the attack from growing. There weren't that many txs to reject. As time passes the chances of making them non-standard to make propagation of such spam txs hard is not looking good. I believe the best (cheapest) solution at this point is to create some sort of side-chain that carries the name Bitcoin (so the scammers can still get their junk hyped) and encourage newbies who buy this junk to migrate there. 1. It's hard to know the reasons for this with certainty. But it looks suspicious enough, specially the early stages of storing massive data in chain. It was done in the dumbest way possible and it is hard to accept it from someone who could read the code, understand the scripts and find the exploit and yet not be able to come up with a less buggy and more efficient way of exploiting it! 2. I think they are as big a problem as they can be. There could be other consequences in the future like government bans because some idiot stored something illegal on chain...