[franga2000]

That's what I used to think, but it does indeed seem to be possible to build a reputation over time. I've been running my own email server for something like 4 years now and emails seem to get through to gmail and outlook accounts almost always at this point.

From talking to other people who tried the same, my theory is that the main reasons for my success were having everything configured well from the very beginning, running on a single static IP for multiple years, hosted at reputable mid-range server provider (not the cheapest, not the most popular) and not sending any "broadcast" email whatsoever for a very long time.