Sunday, April 08, 2007

Each Twapper update costs P4.53 (est. only)

For some time, I'd been looking for a cheaper way to send Twitter updates. Without a Philippine SMS center, each update via SMS message to Twitter's UK number costs me around P15 per message.

It was therefore hard to contain my excitement when I finally figured out how to use the Twapper feature in 30boxes Mobile to send my tweets. By my back-of-the-envelope estimates, it costs around P4.50 per update when I use Twapper.

That computation is based on the following assumptions (please feel free to correct my math):

  • I transfer roughly 8 to 12 kb of data each time I load my Twapper page (without images), according to my Treo's web browser.
  • Let's just use 15kb per page refresh to be on the safe side.
  • I typically load the page twice whenever I post:
    1. To access the form for posting, and
    2. When the page refreshes to let me know if the update is successful.
  • For the sake of simplicity, let's assume that I use the full 140 characters for all my 'tweets' (140 bytes)
  • Let's add an admittedly arbitrary overhead of 50% to the tweet for authentication and other handshaking. This means the update itself requires at least 210 bytes or 0.2 kb
  • Globe (my mobile provider) charges P0.15 / kb of transfer
  • 15kb + 0.2kb + 15kb = 30.2 kb per update
  • 30.2 kb * P0.15/kb = P4.53 per Twitter update via Twapper
Paying P4.53 per update is a lot more acceptable than P15, IMHO.

Caveat: this computation does not yet factor in all the typical post-paid billing adjustments (currency adjustment, VAT, etc.) that will, of course, apply.