What is the number under my user ID...?

It's the number of posts you've made

I guess that mentions how many number of friends you are having in your list. I am not very sure about this. I feel it cannot be how many number of posts you have made. Will check this out and later will again post it here.

The number which you see under your username is your Rank. The more activities you make here, the more will be your activity rank. [b][/b]Your rank will increase by one when you respond to new discussions [b][/b]Your rank will increase by One when you start a new discussion & when some one responds to it(only for the first response) [b][/b]you rank will increase when you comment on others discussion where you have not responded. You need to achieve certain rank before you can enjoy the complete features of myLot. Example, you need to reach a rank of 200 to use smileys & a rank of 500 to use 'Copy Paste' & uploading photos. Happy Lotting