Letting people know your product exists is fine. State of the art advertising, that is, propaganda aimed at maximizing sales, seems to have forgotten about ethics. I'd argue that advertising as a practice today is more evil than neutral or good.

>You think advertising is 'evil'?

Maybe they do, but using the idiom “necessary evil” doesn’t make it certain that they do. Probably nearly nothing colloquially described as a “necessary evil” is actually “evil”. It can be only a pain or an annoyance, but required.

>[…] the use of the term "evil" in the phrase does not necessarily indicate that the thing being characterized as a "necessary evil" is something that is generally considered an "evil" in the sense of being immoral or the enemy of the good.

— https://en.wikipedia.org/wiki/Necessary_evil

I'm using the common idiom, I don't think it's actually evil but in my opinion it's definitely a fundamentally negative practice that is unfortunately required to be used in the process of doing something otherwise positive. Servers and programmers aren't free, and if what you're doing is positive then you're still socially net positive despite the negative impact of advertising.

I'm not saying that all advertising is bad either, it's the specific case of B2C online advertising that compromises privacy and massively reduces the signal:noise ratio of the platform you're using. Sales and marketing aren't inherently bad in themselves, obviously.

Listing in a local newspaper in a section devoted to listings of such things is perfectly fine and desireable. Placing your ad anywhere where users do not explicitly go to look for such information that the ad offers is evil, yes.