I've got a section in my bookmarks called "product ideas." Every time I see an article on the internet that I could potentially turn into a great product, I bookmark it to this folder.
Sometimes, I just stumble upon great ideas. But most of the 100+ articles I have in this folder, I got from digg.
What I do is go to Digg about once a month and look at the most popular articles for the last 365 days. Many of these articles have received thousands of diggs. Do you think there might be some interest there????
I have found that the health category gives the best ideas, but all of the categories do well for this.
Also, I look for list type articles. For instance, here's an article I've got bookmarked but don't have time to develop right now:
25 Killer Actions to Boost Your Self-Confidence | Zen Habits
This lists 25 different things you can do to develop your self confidence with short (20 -25 word) descriptions of the activity.
Can you see picking 10 of these activities and writing a page or two about each one? Voila, you've got yourself a short report!
Stacy