I would target email addresses, and would collect them by doing Show HN launches for content that is very easy to make, like curated and aggregated lists/links,

I would target email addresses, and would collect them by doing Show HN launches for content that is very easy to make, like curated and aggregated lists/links, newsletters that never get written, or services that are a thin layer over an API. Stuff that could be created within a day. When they were submitted I would wait until someone legitimately upvoted it. If it does get a real vote I would arrange an additional upvote from a HN user. At that point it will probably climb into the bottom 20 of the front page at least for a little while. I would use a different product, domain, submitter account and helpful upvoter each time.