Are any of your friends using Bell, Rogers, or TELUS? Check this out! Each of these carriers let you send text messages to people on their network for free, in your browser. Does anyone know if WIND Mobile has something similar? Also, the Rogers one requires you to sign in before you can text. So, if you’re not a Rogers customer, you can’t use this one.
Another thing you could use this for is determining which carrier a number is using. Enter the number in these sites and if one works, you’ve got your answer.