I’m guessing some of the stuff Porcupine said (albeit mostly correct) might be a little above the scope you were expecting.
I think you’re mostly concerned with methods of marketing a page (and thusly a product) and also this idea of “automatic SEO”. Let me try to address those clearly for you.
SEO, or rather more accurately, Organic SEO is the process of getting your website to the top of the search rankings for keywords your audience is searching. In this manner, you get traffic when people click your website in the search results.
On the other hand, with web ads, you pay for space on websites or search engines and hope people click through to your site. This generates traffic to your site as well.
You could do SEO, or advertising, or both…and bring traffic to your site. There are pros and cons to both. It’s up to you which one you choose, and it largely depends on the website, the type of product, target audience and other factors. Money is of course a big factor, and those without a big ad budget lean toward SEO – but SEO costs money too unless you do it yourself.
So that leads me to the next issue. If you want a successful website, you will completely abandon and forget about any concept that even resembles something called “Automatic SEO”.
There’s no such thing, and no matter what tool or resource you use to TRY to automate SEO, you will never get the level of optimization you need comparable to doing it all manually. It’s a good amount of effort and takes some expertise and experience.
If you want to get traffic, and spend less money on the marketing budget, learn SEO and do it manually. Feel free to send me a message sometime if you have any specific questions about SEO that you need help with.
Oh, and one more thing… the answer to your title question, what’s the purpose of a web page? To inform, entertain or sell something, or to act as a portal for a web-based service.