the standard, is to have your name at the bottom. just in case you get a text message from someone who isn't in your phone book, you can look at the name at the bottom. Esti. Chaya. now you know who it was who sent that to you. but then it wasn't enough to just write your name. you have to use as many symbols as you can. S became $, a became @, even i can be replaced with !. sometimes it could take awhile to figure out the name, but if you know the person who is texting you, you should have no problem.
some people like to go a step further, and leave little messages at the bottom of their text: "Have a super day!" or "Smile, it's all for the best!" not that i don't appreciate little inspirational reminders. it's just a funny place to leave them. i have one friend who has such long signatures, that she always has to send her messages in two texts, because it takes up half of her allotted characters. or she leaves, what she thinks are inspirational messages, but to me sound like she got them out of the New Testament.
then there are those who have bizarre or cryptic signatures. sometimes it's a private joke. sometimes it's just a random assortment of letters. sometimes it's a word that's spelled so badly, or missing all the vowels, so you can't understand it. my aunt has a policy that she won't answer any text message unless she understands what the signature is about, but i suspect she only employs that policy when i text her.
although i must admit that i too have been guilty of slightly cryptic signatures, they are usually either Latin phrases (cogito ergo sum,dum spiro spero), or Hogwarts spells (petrificus totalus, coloromuto) but for the most part, i use texts to get a message across, or have a conversation, and i don't really see the big idea in changing your signature everyday, depending on your mood.