I've done a few searches for niche specific email lists for my business and from what I can tell it's a major no no nowadays to buy any kind of email list unless they double opted in to your personal list.
Recently I found the term co-registration lists and thought maybe that's a more ethical way of quickly building your list.
Within the last week or so I've learned to offer a free eBook/report/download in exchange for email sign-up so I've got that but I know it will take a few months to build a decent list.
What are your thoughts on building a list the right way quickly?
EDIT: So sorry, I meant to post this under Email Marketing!