Ideas sites are designed for the capture, categorization and ranking of ideas. As such they are well-suited for ideas contests, client feedback, or company brainstorming.
Folks we interview submit (in our case) five ideas. We then flip that into a traditionally-formated interview on our blog. Doing this sort of combination blog-ideas interview has five nice advantages:
1) Speed: When conducting interviews, you don’t need to conduct a live interview. You just need your interview subject to enter a few ideas that you then reformat as an interview. Your subject can also comment on ideas that are already there.
2) Publicity: Once the interview is ready, you can publicize the interview overall. You can also publicize individual ideas contained in the interview.
3) Search: From an SEO perspective your interview will get good exposure, because both the interview and the component ideas have their own pages.
4) Engagement: Using this dual format, readers can comment on the interview overall on the blog or on individual component ideas in the ideas area.
5) Archive: Most importantly, all of the ideas in the interview will be captured, categorized, and ranked against similar ideas. This gives the interview a longevity often missing with blog posts alone.
There are likely other applications for ideas sites (conference and meeting notes come to mind). With respect to interviews, an ideas platform not designed for that purpose actually works quite well.