I see you point. Certainly, if a blogger is constantly spamming HN and other social news sites it's kind of a annoying.

On the other hand, that's the whole point of social aggregation: to democratically filter the good stuff to the top. Some variation in submission is good, as long as there's not too much off-topic spam.

It's a hard balance.

Social news sites are the perfect venue for (non-advertising) bloggers to self-advertise. If someone thinks their own blog post is relevant, why not post it to hacker news? Why shouldn't a blogger think all his articles are relevant?