The auto-correct feature on our cell phone makes it harder to send a correct message also. It takes something we meant to say, converts it to what it thinks it should be, and (if we aren't careful to notice how it changes words) sends something we didn't mean or that doesn't even make sense. For instance, take "jpg" (a file extension for photos and images). Auto-correct will turn that (when used by itself) into "jog" which changes the meaning and makes no sense in the rest of the message.
So our challenge in posting to Twitter, Facebook, Instagram, Goggle +, Linked-In, or other social media sites, or in sending someone a link to a page or article we want them to visit or see, is that we use the correct string of numbers and letters for that web address or that we otherwise spell words correctly.
Sometimes, references that are posted inside other articles don't do this as diligently as they should. As a result, we share references with people that don't work. Before sharing any we address with anyone that we expect to go to that site, open it, and then or watch the content, we need to try to open it first. It might not work.
There might be - and has on several occasions - been an extra or extraneous character, number, or word that renders the address unusable. It simply won't open as it is entered. Therefore, we need to visit that site as best we can, determine what part of the address needs to be adjusted or modified to make it usable for someone else, copy that corrected address, and send it to others that we want to visit the site and use what they will find there.
It could even be the way a page displays in the address bar after it opens, but copying that address and attempting to use it to find that site again just won't work. Generally, go with the fewest number of characters that are possible - look for a grouping right after the ",com" or other domain extension and go with that to see what happens. It may take more than one attempt to decipher the correct reference to share with people, but it is worth it. Otherwise, the site simply can't be shared.
So, we want to do the detective work and go to any site before passing along the address to someone else. It might work - great! It might not. That's when we have to go to work to figure out (if we can) what specific string of words or characters actually takes someone to that site.
Not doing so is a little like telling someone to call a certain phone number or to show up at a meeting or appointment at a particular address without ever determining that they are valid or that they have been written down correctly.
While upper or lower case typically does not matter in a web address, and is used for effect, branding, or as a way of separating words, punctuation (watch out for a comma instead of a dot - commas are never used in an address), spelling, and the correct use of additional characters does matter.