Google Ads

I've just signed up for Google's AdSense program to see if putting ads on my site is a viable way of earning a bit of extra to cover my expenses. Granted my site doesn't generate _that_ much traffic, but still, maybe...I'll be trying out different positions and layouts trying to make it as unobtrusive as possible. I'll be testing it for 3 months to see how effective it is. Please post your thoughts and opinions on this matter here. Constructive arguments only.