I'm catching up on Seth Godin's blog, and he has a post which I found interesting. In it he debates himself as to what the "best" strategy is when it comes to (A) advertising others and (B) advertising yourself on a blog. He says he "doesn't know". Of course, he does know, he just hasn't really put it together.
The fact of the matter is that there's no permanent "right way", nor will there ever be. There are niches we fill, and these niches change over time and what passes for space here in the online world. The key is to know what niche you're in and how you can act while in that niche.
Seth isn't advertising his products enough, flatly speaking. He takes the "high road" and only mentions his products a few times ever - in a blog that generally posts twice a day. This is noble, but it totally misunderstands the nature of who he is, where he is, and what he is offering. It is the approach of a man who is used to writing books, and subconsciously expects his blog to be read in one chunk, rather than in tiny pieces over days and weeks as he writes it. It is the subconscious expectation that all posts will be given equal attention, rather than some posts being speedbumps and others being freeways.
What he sees is: "I just talked about that a few (10? 12?) posts ago. That's pretty recent. They'll think I'm greedy or self-absorbed if I post another post on the subject."
That's the standard line of thought: your blog is more important to you than to anyone else. You are hypersensitive and, more importantly, you don't have any sense of the amount of time and material passing through your audience between their visits to your blog.
What an audience sees is a tiny blip. They see a post that takes fifteen seconds to read on a blog which takes five to ten minutes a day. Aside from the fact that people need to be reminded for dozens of reasons, it's also virtually impossible that someone will be offended by a tiny blip of an ad that is utterly on-target. It's like going into an art store and seing a print of the Mona Lisa on the wall with a little price tag. Are you ever going to get upset by it? No! It's a good product in the right place, and it doesn't exactly get in your way.
As a matter of fact, it's more irritating when he works ads into the body of otherwise unrelated posts, like he did in the post linked above. It's out of place and detracts from the flow of the post.
All it comes down to is the difference between greed and eagerness. Greed is what comes out when you have 25 ads and pimp yourself every day. Eagerness is when you talk about products you think are great - whether they be yours or others - enough to make people remember that they are great.
To do less is to underestimate your worth and to serve your audience poorly.