There currently is no auction. When an auction is created, it will be linked at the top of this page.

Forum ad slots are auctioned off periodically. Here is the current auction. Here are the ad stats. See the current auction thread for more info.

In addition to the inhouse forum ads, it is common for forum users to sell ad space in their signatures. These ads are not intermediated by bitcointalk.org in any way. If you are interested in advertising in this way, it is recommended that you hire a signature manager.

Main slots (1 in 10 chance)

Nine are auctioned off. One is the factoid slot.

Factoid slots (1 in 570 chance)

The tenth slot is usually reserved for these factoids. Occasionally the tenth slot is instead temporarily sold (at a higher-than-normal rate) when somebody is desperate to buy it; in these cases, there is temporarily no chance of a factoid appearing.

Factoids fall into two categories: First, anyone can request that a factoid be added (for free) if it would be helpful to the community. The factoid can be a short bit of info or a simple, mostly-unstyled link. Links to for-profit sites/projects are much less likely to be accepted. Create a topic in Meta if you would like to request a factoid, and the community will debate whether it is actually sufficiently useful to be added. Second, anyone who can see the private Donators section is allowed to add one factoid with few restrictions; this type of factoid explains the existence of the few clearly-for-profit factoids.

• "Governments are good at cutting off the heads of a centrally controlled networks like Napster, but pure P2P networks like Gnutella and Tor seem to be holding their own." -- Satoshi
• "There should not be any signed int. If you've found a signed int somewhere, please tell me (within the next 25 years please) and I'll change it to unsigned int." -- Satoshi
• "You Asked For Change, We Gave You Coins" -- casascius
• "The nature of Bitcoin is such that once version 0.1 was released, the core design was set in stone for the rest of its lifetime." -- Satoshi
• "With e-currency based on cryptographic proof, without the need to trust a third party middleman, money can be secure and transactions effortless." -- Satoshi
• "In a nutshell, the network works like a distributed timestamp server, stamping the first transaction to spend a coin. It takes advantage of the nature of information being easy to spread but hard to stifle." -- Satoshi
• Make sure you back up your wallet regularly! Unlike a bank account, nobody can help you if you lose access to your BTC.
• "Bitcoin: the cutting edge of begging technology." -- Giraffe.BTC
• Every time a block is mined, a certain amount of BTC (called the subsidy) is created out of thin air and given to the miner. The subsidy halves every four years and will reach 0 in about 130 years.
• The block chain is the main innovation of Bitcoin. It is the first distributed timestamping system.
• Once a transaction has 6 confirmations, it is extremely unlikely that an attacker without at least 50% of the network's computation power would be able to reverse it.
• Even in the event that an attacker gains more than 50% of the network's computational power, only transactions sent by the attacker could be reversed or double-spent. The network would not be destroyed.
• According to NIST and ECRYPT II, the cryptographic algorithms used in Bitcoin are expected to be strong until at least 2030. (After that, it will not be too difficult to transition to different algorithms.)
• The forum was founded in 2009 by Satoshi and Sirius. It replaced a SourceForge forum.
• "This isn't the kind of software where we can leave so many unresolved bugs that we need a tracker for them." -- Satoshi
• "Bitcoin: mining our own business since 2009" -- Pieter Wuille
• Unlike traditional banking where clients have only a few account numbers, with Bitcoin people can create an unlimited number of accounts (addresses). This can be used to easily track payments, and it improves anonymity.
• Even if you use Bitcoin through Tor, the way transactions are handled by the network makes anonymity difficult to achieve. Do not expect your transactions to be anonymous unless you really know what you're doing.
• Bitcoin addresses contain a checksum, so it is very unlikely that mistyping an address will cause you to lose money.
• The Bitcoin network protocol was designed to be extremely flexible. It can be used to create timed transactions, escrow transactions, multi-signature transactions, etc. The current features of the client only hint at what will be possible in the future.
• The network tries to produce one block per 10 minutes. It does this by automatically adjusting how difficult it is to produce blocks.
• Each block is stacked on top of the previous one. Adding another block to the top makes all lower blocks more difficult to remove: there is more "weight" above each block. A transaction in a block 6 blocks deep (6 confirmations) will be very difficult to remove.
• Transactions must be included in a block to be properly completed. When you send a transaction, it is broadcast to miners. Miners can then optionally include it in their next blocks. Miners will be more inclined to include your transaction if it has a higher transaction fee.
• Whoever mines the block which ends up containing your transaction will get its fee.
• Remember that Bitcoin is still beta software. Don't put all of your money into BTC!
• The Bitcoin software, network, and concept is called "Bitcoin" with a capitalized "B". Bitcoin currency units are called "bitcoins" with a lowercase "b" -- this is often abbreviated BTC.
• The forum strives to allow free discussion of any ideas. All policies are built around this principle. This doesn't mean you can post garbage, though: posts should actually contain ideas, and these ideas should be argued reasonably.
• If you want to be a moderator, report many posts with accuracy. You will be noticed.
• If you see garbage posts (off-topic, trolling, spam, no point, etc.), use the "report to moderator" links. All reports are investigated, though you will rarely be contacted about your reports.
• "I'm sure that in 20 years there will either be very large transaction volume or no volume." -- Satoshi
• "Your bitcoin is secured in a way that is physically impossible for others to access, no matter for what reason, no matter how good the excuse, no matter a majority of miners, no matter what." -- Greg Maxwell
• NastyFans - The UNOFFICIAL Nasty Mining Fan Club
• VPN's and Cloud Backups made simple. crowncloud.net
• I HATE TABLES I HATE TABLES I HA(╯°□°）╯︵ ┻━┻ TABLES I HATE TABLES I HATE TABLES
• 
• You can see the statistics of your reports to moderators on the "Report to moderator" pages.
• Bitcoin mining is now a specialized and very risky industry, just like gold mining. Amateur miners are unlikely to make much money, and may even lose money. Bitcoin is much more than just mining, though!
• It is a common myth that Bitcoin is ruled by a majority of miners. This is not true. Bitcoin miners "vote" on the ordering of transactions, but that's all they do. They can't vote to change the network rules.
• "If you don't want people to know you're a scumbag then don't be a scumbag." -- margaritahuyan
• There are several different types of Bitcoin clients. The most secure are full nodes like Bitcoin Core, which will follow the rules of the network no matter what miners do. Even if every miner decided to create 1000 bitcoins per block, full nodes would stick to the rules and reject those blocks.
• There are several different types of Bitcoin clients. The most secure are full nodes like Bitcoin Core, but full nodes are more resource-heavy, and they must do a lengthy initial syncing process. As a result, lightweight clients with somewhat less security are commonly used.
• Be very wary of relying on JavaScript for security on crypto sites. The site can change the JavaScript at any time unless you take unusual precautions, and browsers are not generally known for their airtight security.
• The grue lurks in the darkest places of the earth. Its favorite diet is adventurers, but its insatiable appetite is tempered by its fear of light. No grue has ever been seen by the light of day, and few have survived its fearsome jaws to tell the tale.
• No Gods or Kings. Only Bitcoin
• What is consensus?
• How can the Bitcoin system be changed?
• What is a hardfork?
• In order to get the maximum amount of activity points possible, you just need to post once per day on average. Skipping days is OK as long as you maintain the average.
• The trust scores you see are subjective; they will change depending on who you have in your trust list.
• You get merit points when someone likes your post enough to give you some. And for every 2 merit points you receive, you can send 1 merit point to someone else!
• In order to achieve higher forum ranks, you need both activity points and merit points.
• Activity + Trust + Earned Merit == The Most Recognized Users on Bitcointalk
• [BPIP] Who are your biggest merit fans? Who do you send all of your sMerit to? .. Do you.. MATR?? O_o
• [BPIP] Bitcointalk Public Information Project - User stats, ranks, reports, web browser extension, and more!
• Who are the least trusted users of Bitcointalk? ¯\_(ツ)_/¯ Who are the most trusted users of Bitcointalk?
• BitcoinCleanup.com: Learn why Bitcoin isn't bad for the environment
• TalkImg was created especially for hosting images on bitcointalk.org: try it next time you want to post an image