The colon is underused as punctuation and overused as an intestinal organ
Check it: colons are incredibly useful for introducing new ideas or adding emphasis. And the way people talk on the internet could use significantly more clarity: you can ramble and ramble, and just talk about whatever, expand on your point, really beat that dead horse, and then take a short break. But using colons allows you to introduce an important new idea: they provide a clear separation between different thoughts.
Oh yeah, about the colon as intestinal organ: idk...stay away from Taco Bell unless you have some extra time
Also underused. Especially in lists. Like, if I want to go to Tokyo, Japan (again); Seoul, South Korea; (<- an Oxford semicolon??) and Bordeaux, France then semicolons are ideal rather than a bunch of commas that make it unclear.
I actually looked up how to use them and this site provides good examples.
Semicolons are pretty neat too; the primary use is joining two related independent clauses without using a conjunction. Some folks seem to enjoy using them interchangeably with an em-dash; others prefer to use em-dashes as a less formal punctuation mark to replace a colon while still adding emphasis.