I recently saw a username on ask ubuntu where half of it was written backwards. How is that possible?!
There are many such tools on the internet, that consist of using normal text characters to make it "look" like the text it reversed or upside down.
One such one I found here - http://textmechanic.co/Reverse-Text-Generator.html Hit the "Upside Down" button
For example my user name would look like this:
An even better one is this - http://www.sherv.net/flip.html
˙noʎ ǝɹɐ ʍoɥ
You can then put this text in your username by changing it in your profile, click on your username the "edit" on the main site.
tђเร เร ς๏๏l!
Writing backwards, as in the characters being arranged in reversed order (ex. below) is achieved through use of the
U+202E character, aka
RIGHT-TO-LEFT OVERRIDE. This is used to force right-to-left writing, mostly for languages that are written RTL (although HTML & CSS nowdays support various ways of achieving that without use of
... nuf si sdrawkcab gnitirW
Please note that this example does not use U+202E, but only emulates the results.
Doing this has various side-effects. Mostly, it breaks some parts of the layout, as it is an override and as such also affects other text and HTML on the same or deeper levels when it is invoked.
Writing inverted, as in the characters being flipped upside-down and then mirrored on the vertical axis (ex. below) is achieved through use of various UTF characters that resemble a "normal" character manipulated this way.
ǝɯosǝʍɐ sı ƃuıʇıɹʍ pǝʇɹǝʌuı ʇnq ˙˙˙
˙˙˙oɹq ʇnoqɐ ƃuıʞʃɐʇ ǝɹ,noʎ ʇɐɥʍ ǝnʃɔ ou ǝʌɐɥ I
I assume you're referring to ObsessiveSSOℲ who is using unicode to make text "appear" upsidedown. It's not a feature of the site at all and can be done on any site.