Keywords are not case-sensitive according to Google Adwords. You don’t have to use separate keywords – like, one for a: 1. lower-case, 2. upper-case and another for a 3. first letter in capital, version of the same keyword or phrase. For example, you will not be given different search results by the search engines for the keywords ‘search engine optimization‘ and ‘Search Engine Optimization‘. So, whether you’re entering keywords into your meta tags or performing keyword research using search boxes from Google, Yahoo! and MSN, your keywords will be matched “without regard to upper-case or lower-case letters“.
On the other hand, when writing for your site’s sales copy, if you’re going to type a proper noun (name of a person, place or thing) in lower-case because you say it’s your keyword and that keywords are not case-sensitive anyway – don’t do it! People who are going to read what you wrote will just see it as a typo error. Be careful on that part. Every time you put up your writing on the Internet, potentially hundreds, or thousands, maybe millions of people are gonna see it. So, do your best to be professional with writing stuff.
Be SEO-sensitive now! Okay?
