There are e-mail spider that allows categorization?, i mean, something like this from the results?: 1.234.212 Emails from web design community 9.334.234 Emails from adult content community 334.212 Emails from tech forums and so on?
Ase everyone has pretty much said, you will need to provide something of value for them in return for their email address. For most people it's a short ebook. After that you'll want them to be part of your list and your email marketing campaign.
First off... how are you collecting your emails?...hopefully its not email harvesting....Try to stay away from illegal habits. List your way of collecting your emails or if you need a post of a list of email list building strategies besides the lawbreaking method
If you provide a free thing on your website in exchange of email ID then you can collect email IDs fast, but again, in this case you need traffic to your website. So, you can use some email IDs tool. I will not recommend the tools like email spider or email extractor, because they collect craps from the internet and produce the same results again and again. You need to use some modern tools like 'acute email ids production engine'. This is the best email marketing tool that can generate country targeted email IDs in a short span of time and can produce different results. You can have thousands of email IDs in a short span of time.