QUOTE: “If you want to stop spam, the most straight forward way to do it is to deny people money because they care about the money and that should be their end goal. But if you really want to stop spam, it is a little bit mean, but what you want to do, is sort of break their spirits. There are lots of Google algorithms specifically designed to frustrate spammers. Some of the things we do is give people a hint their site will drop and then a week or two later, their site actually does drop. So they get a little bit more frustrated. So hopefully, and we’ve seen this happen, people step away from the dark side and say, you know what, that was so much pain and anguish and frustration, let’s just stay on the high road from now on.” Matt Cutts, Google 2013
You don’t want to “keyword stuff” and cram your core keyword and every possible variation of it into your alt attribute. In fact, if it doesn’t fit naturally into the description, don’t include your target keyword here at all. Just be sure not to skip the alt attribute, and try to give a thorough, accurate description of the image (imagine you’re describing it to someone who can’t see it – that’s what it’s there for!).
QUOTE: “So sites that don’t have much content “above-the-fold” can be affected by this change. If you click on a website and the part of the website you see first either doesn’t have a lot of visible content above-the-fold or dedicates a large fraction of the site’s initial screen real estate to ads, that’s not a very good user experience.” Google 2012
Your SEO keywords are the keywords and phrases in your web content that make it possible for people to find your site via search engines. A website that is well optimized for search engines "speaks the same language" as its potential visitor base with keywords for SEO that help connect searchers to your site. Keywords are one of the main elements of SEO.