Because someone who is looking for something that specific is probably a much more qualified searcher for your product or service (presuming you're in the blogging space) than someone looking for something really generic. And because long-tail keywords tend to be more specific, it's usually easier to tell what people who search for those keywords are really looking for. Someone searching for the head term "blogging," on the other hand, could be searching it for a whole host of reasons unrelated to your business.
Wow! This was so helpful to me. I am new to the blogging world and have been feeling really frustrated and discouraged because I lacked the knowledge of getting my post to rank in search engines. I know there is a lot more I still need to learn but this has layed a foundation for me. I am bookmarking it so I can return and read it again. Thank you for writing!
SEM results show to a select target audience. SEO results do not. While successful SEO and SEM strategies are driven by a plan to connect with a select audience, you can only specify that target audience through SEM. Through SEM, you can (depending on the publisher) select what audiences you want to see the search results by assigning filters based on age, location, income, habits, and more. Through SEO, you cannot specifically choose who will see your search results.
In March 2006, KinderStart filed a lawsuit against Google over search engine rankings. KinderStart's website was removed from Google's index prior to the lawsuit, and the amount of traffic to the site dropped by 70%. On March 16, 2007, the United States District Court for the Northern District of California (San Jose Division) dismissed KinderStart's complaint without leave to amend, and partially granted Google's motion for Rule 11 sanctions against KinderStart's attorney, requiring him to pay part of Google's legal expenses.[70][71]

Consider the average cost-per-click in your industry. Before deciding that SEM is right for your business, research and consider how much you’ll need to spend to show in paid search results. Keywords have varying cost-per-clicks based on competition. If your cost-per-click is low, it might be the right strategy for you. On the flipside, a very high cost-per-click might make you decide you’re better off focusing on SEO.
QUOTE: “We do use it for ranking, but it’s not the most critical part of a page. So it’s not worthwhile filling it with keywords to hope that it works that way. In general, we try to recognise when a title tag is stuffed with keywords because that’s also a bad user experience for users in the search results. If they’re looking to understand what these pages are about and they just see a jumble of keywords, then that doesn’t really help.” John Mueller, Google 2016
QUOTE: “alt attribute should be used to describe the image. So if you have an image of a big blue pineapple chair you should use the alt tag that best describes it, which is alt=”big blue pineapple chair.” title attribute should be used when the image is a hyperlink to a specific page. The title attribute should contain information about what will happen when you click on the image. For example, if the image will get larger, it should read something like, title=”View a larger version of the big blue pineapple chair image.” John Mueller, Google
Goals and Objectives. Clearly define your objectives in advance so you can truly measure your ROI from any programs you implement. Start simple, but don’t skip this step. Example: You may decide to increase website traffic from a current baseline of 100 visitors a day to 200 visitors over the next 30 days. Or you may want to improve your current conversion rate of one percent to two in a specified period. You may begin with top-level, aggregate numbers, but you must drill down into specific pages that can improve products, services, and business sales.