I've had several great ideas on how to build a site or what content to create for months now, but the lack of time doesn't allow me to do much.
As time passes by, I notice people doing what I thought would be a good idea or already developed sites, right what I was thinking about. This was and is not only amuzing, but also interesting.
For example, I've noticed this phenomenon a while ago and surely enough, Aaron Wall finally writes about sharing your ideas now (with more examples of this lazy bloggers plague).