Hey @metama! I think you are asking some great questions that need to be answered. Personally, I do not see a problem with advertising on the Steem blockchain, but if we don't talk about it as a community, I can see Steem become like the wild west where everything goes.
I just checked out the Steem FAQ about spam (https://steemit.com/faq.html#What_is_considered_spam_or_abuse). None of the points specifically states that advertising is spam, but I see a few points that people may use to argue that it might be spam.
Ultimately I think it is up to the Steem community to make these types of decisions. Even without a formal stance on adverstising, each account can downvote a post (for any reason), and we can upvote as well. There also is not a formal stance on bidbots, and as we have seen over the years, there is still a division among the community about this topic.
Personally, I do not always like what I see on the Steem blockchain (topics, behaviors, etc), but I would prefer to err on the side of letting individual freedom win out as long as it does not impose on the individual freedom of others.
So if you want to use a bid bot to advertise, then go for it. Just make sure that you are not infringing on someone else's legal rights and individual freedoms. If someone does not like it, then express concerns in the comment section or via downvotes/flags.
My biggest question is whether or not advertising will be a resource made available at the account level, or if the operators of the different Steem frontends will plaster advertisements on their UIs for their own gain.
well said @sumatranate ... I don't see this as any different than a personalized blog ... and with the advent of dclick (and hopefully similar services) I see advertising making it's way to the steem blockchain no matter what ...
now, what will be interesting is how people use it and how it impacts the user experience