The worst thing you can be online is stale. It’s easy to see who updates their website or blog regularly, and who doesn’t. But updating your website with the same material isn’t enough if you want to keep your readers interested.

You need new content and something fresh and original for your audience to look at. Naturally it should illustrate your main points on your site as well.

To show main source of content:
http://www.onextrapixel.com/2014/02/07/from-illustrated-maps-to-antique-photos-5-content-ideas-you-havent-triedyet/