That being said, I don't think there's anything particularly wrong with accounts that exist specifically to submit a given site's content (even programmatically), since that content must be still democratically approved by the user base. I think vote-brigading is a much more serious issue, and one that HN seems to deal with well.
Plenty of people submit their own content. In fact, it's encouraged. You have reddit confused with digg, somehow.
From reddiquette.
Once, someone submitted one of my blog posts about a rather interesting bug in a AAA game to /r/programming. Over 1,000 net score. Out of curiosity, I submitted the same post myself to /r/games. -7 score.
> If over 10% of your submissions are your own site/content, you're almost certainly a spammer.
[1] http://www.reddit.com/wiki/faq#wiki_what_constitutes_spam.3F
At least I try to always make good submissions, and usually HN only let me submit twice every month...
When I joined HN I submitted a lot, but suddenly I could not submit for two weeks, then sometimes I can submit twice or three times in a week, and then have to wait two weeks again...
Why does it matter who does the submitting?
Dailydot, extremetech, pcmag, geek, macobserver, betabeat, itworld, bostinno etc have collectively operated dozens of acounts to spam their own stuff, none of which met an actual community member's standards for submitting a story.
Individuals submitting their own blog posts and especially with success are usually so low volume they're not even noticeable unless they overdo it and inevitably get called out for it.
I prefer to say "could" instead of "have" unless you have definite evidence.
Plus dailydot are just getting started with the OP + 'sexyalterego'.