The four most efficient ways of expanding your e-mail database

Some people consider e-mail campaigns obsolete, yet some still consider them necessary. This discrepancy is rooted in the fact that it's the quality of the contacts in the database that's very important. While the success rate of the e-mail being opened is between one and two per cent in low-quality databases, this rate increases significantly with high-quality contacts. Here are the four most effective ways of building your own quality e-mail database and increasing the success rate of your mass campaigns.