SMS are not 160 characters long, they are 140 bytes long! This is what I discovered today after my SO complained that her mobile operator was charging her for SMS she never sent…
And when you know how computers are working, it totally makes sense!
“So what?” are you going to ask? So, this is again a nice example of character encodings drive you crazy. According to wikipedia there are 3 encodings used in text messages which respectively use 7bits, 8bits and 16bits to encode a single character.
Depending on the characters you used in your message your phone is going to decide what encoding to use, thus reducing the maximum number of characters to, respectively, 160, 140 and 70 (and even less, see later). Any extra character will lead to the splitting of your message into multiple SMS and, obviously, a raise in your bill.
By default the 7bit encoding used is GSM 03.38, which has the following 128 characters alphabet: @, £, $, ¥, è, é, ù, ì, ò, Ç, LF, Ø, ø, CR, Å, å, Δ, _, Φ, Γ, Λ, Ω, Π, Ψ, Σ, Θ, Ξ, ESC, Æ, æ, ß, É, SP, !, “, #, ¤, %, &, ‘, (, ), *, +, ,, -, ., /, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, :, ;, <, =, >, ?, ¡, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, Ä, Ö, Ñ, Ü, §, ¿, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, ä, ö, ñ, ü, à
If you use only those characters, then you text messages can have 160 characters, however, any character outside of this alphabet will mean the use of a different encoding. And if you are using exotic scripts, your messages will be encoded in UTF-16 and in this encoding a Chinese character, for example, will take up to 4 bytes, reducing the maximum length of you Chinese message to 35 characters max.
I guess that now that smart phones are supporting international scripts and transparently breaking up text messages, a lot of people get trapped. The only recommendation I can think of is to enable your phone to display the character count when you type text messages, I noticed that my iPhone is changing the maximum number of characters according to the encoding it’s going to use to send my message.
If you want to know more about character encodings I absolutely recommend the following article by Joel Spolsky: The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)
UPDATE: At Stephanie’s request here is how to activate message count on your iPhone (at least on my 3GS with iOS 4.1).
Go to your iPhone settings, scroll down to “Messages” then toggle “Character Count” on. When you write a text message the count will show up only if you have at least two lines of text :)

Facebook Pages Notifications
This is a problem for most page administrators and there is a 32 pages long (and growing) thread with people complaining about this missing feature. This is a problem because without such a feature you have to periodically crawl your own pages to check if anyone posted anything (status or comment) and get the opportunity to eventually respond to it, or spam it. I guess that since they won’t get notified about this thread the Facebook people will never notice the problem…
One proposed solution to this issue is to “like” each and every status update you post on your pages wall, however, beside the fact that liking everything you post may look a bit awkward, this does not gets you notified when someone posts a new status.
I have some pages I need to watch, so missing this feature was really a problem to me. And when it itches, I scratch… Besides, I wanted to experiment with the new Facebook Graph API.
So I created this application, it’s called “Watch My Pages!” and provides users with receiving daily e-mail notifications when someone posts a status or writes a comment to their pages wall. If you like it, have a problem with it or think about a feature, just drop a message on it’s wall, I’ll get notified ;)