The double plat shows as the amount you get. For example, one offer yesterday may have been 7 plat but today it is 14 - WYSIWYG. The GoDaddy one is particularly stellar if you are new customer

To see the offers:

log into your AL account and click on the STS Nexus button on the character screen where you click 'Play' (this button is located at the top of your screen)
Click the offers tab if not already there (landing tab by default)
Choose either Platinum Offers from TrialPay or Platinum offers from W3i
Each will take you to a screen where you can see the available offers and how much plat you will receive for each one completed.

*Personal Anecdote Here* I tend to do only the ones that require to download a game or app from the itunes store (for iOS users) none of the survey or other offers unless they are from a reputable/familiar company (godaddy, bigfish games). Id say that for me, the W3i offers only complete about 60% of the time...

Check out the link Sam posted in the thread above, good info there. Thanks STS for this great promotion!