Seeding is placing or submitting information about your startup, business, app or product on sites around the internet. While this can be shady if done in a salesy way, it can also be very positive if done legitimately.
The link backs are also great for SEO!
Attached is a list of site you can post or submit a tip to. Be sure to approach them all in a genuine and personal manner for best chances of being listed.
Seeding paired with lots of guest blogging (both in the right places relevant to your industry and audience) will create the perception of you being everywhere and hot. Hot news gets covered - this perception will help when you reach out to potential writers who will most likely already have seen a few things about you.