KnowYourOnions.com is a mobile recipe service. You text in a few keywords (tags of the recipes) to a short code. Within a few seconds you receive a SMS reply with a recipe suggestion based on your keywords including a list of ingredients you have buy to prepare it. You then also get forwarded to a mobile version of the recipe page.

More information about this project can be found under http://knowyouronions.com/how-it-works/

You might have a lot of content which needs to be available on the go. Just put it in a WordPress database and add unique tags to the pieces of contents. Any of the content can now be retrieved at any time via the tag you've set. Think of shopping information, vouchers, pickup lines or sports results.

You might have a mobile version of the blog, for example by using WPTouch. You might want to advertise a keyword which allows people to retrieve the mobile link via SMS. Just set the reply text to the link to the mobile version of your blog item and your users are able to request the link via SMS.

You might be running a blog with short text content. Your audience would be able to retrieve the content via SMS keyword. Any post can be retrieved via SMS, given its not too long.

The possibilities are endless.