Although I don't follow the blogosphere much, it seems to me that one recurring theme these days is the issue of journalistic ethics as applied to blogs. For instance, what if a blog accepts money to endorse and run favorable reviews about some product, but does not disclose this?
At first glance, this seems a little slimey, but upon further inspection, if some guy in his basement wants to put something on his web page and someone else wants to pay him for it, what's wrong with that?
But then where does that leave other bloggers who want to be taken more seriously? We don't want to have to discount all news and reviews on blogs out of suspicion that they might be astroturf. For example, a recent article which was the subject of a SlashDot story implies that s/he doesn't really trust any blogs because of this: "There's this belief that blogs are more heartfelt and honest. In many ways I think that's true, but I also think that a guy running a blog out of his house likely doesn't hold himself up to the same ethical and moral standards as does a professional site."
My proposed solution is to create multiple semi-standard "codes of ethics" which various bloggers can then voluntarily state that they ascribe to. For instance, there would be one code of ethics for people intending to be impartial, accurate, and fair. Another one for people who post whatever unsubstantiated gossip they hear about, but who promise to disclose any conflicts of interest and to never deliberately spin an issue. Etc. The concept is sort of like CreativeCommons standard copyright licenses, or like the attempts at standardized privacy policies.
The guy in his basement does not have to subscribe to any of these codes, and we can be a little suspicious of him. The aspiring indie journalist types can declare their allegiance to some code of ethics, and then we expect more of them.
It's nice to hear people say that they adhere to this or that Code, but that doesn't mean they actually will.
One way to deal with this is the way we do today; WordOfMouthReputation?.
Another way would be the creation of certifying authorities. These would be small organizations which trademark a "stamp of approval" emblem and only allow you to display that emblem if you can meet certain criteria.
These would be AmateurJournalistAssociations?. But journalist associations already exist, so why create new ones?
To make the barrier to entry low, one would not want to make the cost of certification very high. But if the cost is too cheap, the association will not have the revenue to pay employees to enforce the criteria.
One solution may be to have grades of certification. The cheapest grade, maybe for $5, might buy you the right to be recorded as a follower of some Code of Ethics, and to show an emblem denoting the same. However, no enforcement is done by the Association unless a complaint is brought, in which case there is a short (cheap) investigation to determine if you should be kicked out. Or perhaps if this is too expensive, no one is ever kicked out, but all complaints are recorded so that any reader can check them out.
More expensive grades would buy some actual policing and enforcement and an assurance of a longer, more fair (and more expensive for the Association) "trial" should there be a complaint filed against you. In other words, if you buy the more expensive grade of membership, you get a different emblem which enables readers to trust you more.
The cheap membership, therefore, is cheap to administer because nothing has to be done (besides recording you as a member) except in case of a complaint.
One proposal for a code of ethics for online journalists is John Hiler's proposed Blogging Code Of Ethics. Here is an article he wrote to introduce it, in which he touches on differences between blogging ethics and mainstream journalism ethics. Some people got annoyed by this proposal  , but it seems to me that they read it as an attempt to create a CommunityExpectation that all blogs would follow this Code. Under the current proposal, it is clear that the Codes of Ethics only apply to those who explicitly choose to abide by them.
Some traditional journalism codes of ethics:
Update: there is an initiative called HonorTags? to get people to self-identify which ethical code they are following:
Right now (Aug '05) the tags are too vague, but I think it's a big step in the right direction.