My worry is just that this service will quickly get marked as a spammer and probably blocked or downvoted as a poster in many places.
Also, I HN it's very useful that the owner/submitter can answer the questions that appear in the comments of the post. The problem with mass submission / spam is that the owner can't mass answer all the comments in all the sites.
You should be very wary about doing that. Some of the link in the list are news sites (eg Mashable). If someone at a news site sees you're spamming them they'll be a lot less likely to cover your startup favourably in the future. While you might get some 'backlink juice' out of it, you could also be burning some very valuable bridges.
It's a faulty way of seeing things, but businesses like that tend to have a fog around them. They don't see the icebergs coming.