This is a sign of character set problems. There are different character sets out there. In the old days they where most commonly 8 bit (one byte), like ISO 8859. That would give the computer 256 different characters to use. That is OK if you only use one language. ISO 8859-1 defines the character set that I would use in the old days here in Norway. That covers all the special characters we use here. We have three letters here that does not exist in English.
The problem arises when you get more international where people have names with special characters used only some places in the world and not others. If two computers use different character sets, a text file would look differently for many special characters. Basic characters like A-Z and 0-9 are mostly safe, but others could look like gibberish.
To solve this, we got unicode: Today it is most commonly UTF-8 that mostly use 8 bits, but for special characters use up to 32 bits (4 bytes).This way we can share texts with all sorts of special characters, and we can all share the same character set as UTF-8 can define more than two million different characters. So now we avoid confusion about wrong characters, but we still need a font that covers the characters we need. Or else we still get problems where the characters are not shown, but replaced with a square sign or something. And to make even more problems: Sometimes programmers handle text as single bytes during text processing because they don't think and can end up cutting a multi byte character in half. Then we end up with gibberish too.
More and more often this will be OK these days. When I started working as a programmer 15 years ago this could be a big problem. Today it is way better, but from time to time we end up with character problems as 8 bit character sets and programming errors shows up from time to time. Programmers often hate character set handling and time zones (and even more so daylight savings) with a passion. The problems looks so simple, but these problems still hit us from time to time and they can be really hard to track down.
I can't say exactly where this problem happens for the post you refer to. But somewhere between the writers computer, through the server and to your computer some sort of character set confusion is taking place.