Which interactive channels startups use the most to start their lead generation activities?

Assuming startups prefer using internet marketing to promote their services/products, I was wondering which interactive channels (display advertising, mobile marketing, email marketing, social media and search marketing campaigns) are startups using the most to start their lead generation activities.

As you might expect, it depends a lot on the business.

If the startup is in an existing category that people are already searching for, then search marketing (paid or organic) usually works pretty well.

If the industry is reasonably contained such that they frequent the same websites/blogs, display advertising on those sites can work well.

If the product itself has a social media component (like a Facebook app), then social media channels can work well.

It all depends on the target market.