Spam is a message, post, or article that is, for the most part, irrelevant. Context is the best guide for relevance.
Spam on the AoPS message boards
Spam on the AoPS message boards can usually be classified as one of two major types. The first is advertising and the second is to raise one's post count. The former is grounds for an immediate ban from the message boards and will always be deleted when caught. The second form is generally looked down upon, but the consequences are not so harsh.
Spam on AoPSWiki
Spam on AoPSWiki is monitored much more closely than that on the AoPS message boards. Absolutely no spam is allowed! Examples of spam on AoPSWiki would be writing stuff that is irrelevant to a topic in that particular article, posting links to irrelevant websites, etc.
However, the AoPSWiki is not opposed to relevant commercial links, so long as they are appropriately placed and topical.
The following is always considered spam:
- Links to websites that are collections of links and advertisements. Just link the most appropriate links where they belong in the AoPSWiki.