There are a lot of reasons that you should care about Unicode. As someone who uses the web, you should know what it is and that representing human language is hard, and thus once in a while ��� and variations will show up. If you’re someone who creates code or prose content for the web, you want to know a little more - I recommend Joel Spolsky’s Unicode primer.
And if you’re a big ol' furry, you should know that there are a bunch of animal-face glyphs, like the one I’m using to indicate link-blog posts here. 😼