Copy is an element of advertisements, but not the finished product. Advertisements have many components.
What started with simple banner and text ads, then skyscrapers and variations of shape, has evoled into a barrage of dozens of different species of advertisements. Their radical difference among each other is the difference in the mechanisms provided by the advertising software technology.
There are the traditional banners, skyscrapers, in-line links, push notifications, emergent windows, fly-ins, pop-ups, lightboxes. There are newer technologies like, omni-channel, and DOOH that may be controversial for detractors of advertising in general and for those that care about their privacy.
Come what it may, the programmatic advertising industry has demonstrated a fierce thirst for growth and as long as the user continues trusting and considering the publisher and its advertisements, only the sky is the limit in the capacity for innovation in the search of catering better to the customer's needs. I mean, if you have consideration for the publisher you don't like or use any ad blockers that would prevent the publisher from earning in exchange for your consumption of the content.
Press releases want to be news, in a sense they are, but ultimately they're a specific type of advertising that's used generally for launchs or grand openings of products or services. Press releases attemp to cover a wide range of channels all at once.
If you're bootstraping and don't have money for paid public relations tactics, like releasing a press release, don't think that you can't get your press release out there with an investment of only time and writing.
There are paid and free ways to circulate a press release through
Not using paid distribution may not get you the result that you seek with a press release, to get journalists interested in your story, still if you do it for the backlinks, it makes sense.
A package of a content document or more with at least one sourced media. It's for journalists to use and spread the brand or company around. The content could be a variation on the press release content format. For instance, a press kit may include a one page with the story of the company and at the bottom of the content a little blurb and link to the company's website.