Some things I forgot to mention:
The formal script is generally written into bamboo slats (much like ) by pyrography; the uniform character size with no ascenders or descenders and the angular shape of the letters are well suited to this. This variant is also used in stone carving. As a rule, anything that is supposed to hold up over time is written in this script: signs, declarations, religious texts, philosophy, etcetera.
The informal script, on the other hand, is written with brushes and soot ink or ink made from crushed zalima leaves (a plant similar to henna) on various materials, most commonly bamboo linen and palm leaves but not uncommonly on other things, including skin (there is a stereotype of scholars always having things written all over their arms). It is written much more quickly than the formal script, and is used for things like notes, letters, labels and other things not meant to last for a long time.
There are exceptions to this, of course, especially over time; many old copies of the rapal ma hani (for instance), which is a very important religious text (I used the first couple paragraphs as the sample text), were written with ink in cursive onto dried stalks of bamboo which were then varnished, generally written in a spiral around the stalk. This occurred hundreds of years before modern South Eresia, before literacy became commonplace, but even in Old Eresia there was a distinction between the two scripts which can also be found throughout modern North Eresia. Modern copies of this text, in particular, are often created in the same way and this style, called aqiryalen cua mop'ancuih (literally "it is painted on large bamboo stalks") is common with poetry and some other literary styles, even though the stalks are heavy and hard to transport so in general writing like this is impractical. It is notable that this style would have been written boustrophedon as well if it were not one single line of flowing text; the left-to-right style only came about with the advent of widespread literacy, when it became accepted that left-to-right is easier. It is actually not uncommon for people, especially left-handed people, to write right-to-left in a mirror image of the left-to-right text, but left-to-right is much more common.
I'd actually like to get my hands on a decently wide stalk of bamboo and write some stuff on it in this style, but that'll probably be difficult.
Edit: I hinted at the orthography differences too, but allow me to clarify how they work:
There is no real standard. There are three major orthography systems, which I will call historical, phonetic and mixed. The historical system is the least used but generally has higher prestige; it writes out all the historical morphemes, allophony and sound change be damned. The phonetic system is the one used in the cursive text above, with regular rules for when different characters occur; if words sound the same, they are written the same. The mixed system is in use in the printed text; regular inflections and certain common words are written like the historical system and allophony is not written, but for the most part it follows the phonetic standard. On the whole, the historical system is seen as extremely stuffy and indecipherable, the mixed system is formal and the phonetic system is casual or, sometimes, uneducated. The mixed system tends to have the most variations within it.
@THC: Feel free to call me Rebecca. I mostly dislike diminutives but hold a special dislike of "Becky."
Also, "looks like Tengwar" is a joke, guys. People used to accuse other people of their scripts looking like Tengwar all the time on this forum. Either that's fallen out of style now, people just missed it or it really does look like Tengwar but I don't think it does; aside from having copious ascenders and descenders, the letter shapes are generally different and it has no diacritics.
By the way, what the hell would a script like this be called? An abjad (since most vowels are omitted)? An abugida? (since the vowels, though their values are omitted, are either implied or not implied)? An alphabet? (since there are distinct glyphs for vowels and consonants)? An alphabjadugida?