The acronym stands for Search Engine Optimization .i.e. Making your website easy for the search engines to find, index and rank highly, which then
makes it easier for your target internet surfer to find you
Backlinks are incoming links to a website . A link from an external page (with different domain or server) that refers to your website are know as backlinks in SEO. A site with a lot of backlinks implies that many other sites link to that site.
It will take a while depending on what results you expect what for. Some keywords might even take number of months or more while others may work after weeks or a month. Perform a thorough keyword and market research first to know. Also SEO is basically a continuous process that never stops.
No, Google even offers SEO advice and a plethora of SEO tools itself. It's an ages old myth that Google fight SEOs. In fact the Google employees and SEO practitioners speak at the same conferences and work together as business partners. Most SEO companies are big clients of Google as they also buy PPC ads from Google.
Remember, White hat SEO do the ethical strategies while Black hat is focus on spamming links.
Black Hat SEO is an illegal and an wrong way of getting traffic as well as backlink for the website.This kind of SEO does not help the website to improve ranking in SERP's.White Hat SEO is the legal way to get backlink as well as get regular traffic for the website.