A few days ago I got a spam message which I was about to delete but finally caught my attention. It was the web www.cuantomedas.com It works so you can randomly vote pictures of people from 1 to 10. Then you can see the rankings.

I think Ideas4all needs an area just like that for the ideas. it is fun, easy to use, and a useful way to maximize the experience of approaching ideas at Ideas4all. I would add an additional tag next to "Top Ideas" "Latest Ideas", etc... called "VOTE IDEAS".
There just as in www.cuantomedas.com , you could randomly vote Ideas, (All of them or defined by category) one by one with an easy interface.

Also, as well as in that web I mention, I would change the voting system from "good" or "bad" idea to a 1 to 10 grading. That will be a lot more useful for users when searching for good ideas as they could easily find those that are a 10, a 9, 8,.....1 (could you imagine how to find really good ideas when Ideas4all has 1 million Ideas?? Just if 30-50% are good, the numbers are incredible!! Grading from 1 to 10 would make Ideas4all a powerful brain engine in the future)

I would also give a color tag to the ideas using a rainbow range (1-10). Intense Blue for the bad ideas ... to violet.. green.. orange and red for the most popular ones. That way it would be easy to find which are the "hottest" ones!

I hope these ideas will help you increase the time expent by an ideator or a questor at Ideas4all. The site would be more fun to use to come back.