I provided this answer on Quora.

https://www.quora.com/What-are-the-most-interesting-new-blockchain-applications/answer/John-Searles-12

The applications of blockchain in generalare quite varied and have already been covered by other comments in this thread of answers. However, most of the potential applications are at the moment, just that, potential, with little or no contact with the systems that they are proporting to solve or enhance. Most at the time of writing this, are speculative, with ideas on how to bring value to them.

The vast majority of Dapps currently in existence are gambling apps or gaming apps. The gambling (whilst interesting in it's proveably fair odds) is perhaps not the most revolutionary application of this technology. Likewise, the gaming, whilst being able to showcase the non-fungibility (unique ownership) of digital assets, quite frankly is pretty poor from an actual gamer's perspective.

There is one chain that I currently interact with on a daily basis (and not for financial speculation) and that is STEEM (and its pseudo stable coin SBD). Originally started as a blogging platform (known as Steemit), the last Hard Fork has laid the basis and the flexibility for a wide array of applications to be built upon the STEEM backend.

Applications already in use (not speculative!) include :

@dsound and @dtube provide services that mimic Spotify and YouTube, whilst providing content creators with a revenue from their audience.

@vimm, a streaming service that mimics Twitch (but with a revenue source)

@actifit is a fitness tracking application that is currently being used, and is beta testing it's Fitbit integration (from what I hear, it seems to be working).

@steemmonsters, a trading card and tactics game that is the equal of any on rival mobile platforms.

@dstors is a new project that aims to be a clearing house for auctions and second sales. With revenue from the chain interactions going to offset the costs of postage (and otherwise rewarding both the buyer and seller).

Blogging platforms like @steempeak, @busy, @esteem and @partiko offer alternative front end access to the chain, and plugins like @steempress allows existing WordPress sites to seamlessly cross post to the Steem chain.

@tasteem is a project that is providing user reviews of restaurants around the world.

@steepshot and @share2steem (cross posting) allow access to Instagram-like interaction with chain.

@fundition is a way of listing projects to be crowd funded. Charity and community projects exist alongside private projects.

@musing is another dapp that mimics the Quora experience (but with questions and answers being rewarded).

@spunkeemonkee is a new iniative to realise a game that aims to educate and inspire children, providing them with worthwhile and achievable daily and longer term goals. At the moment, it is in beta, accessible via Web browser, but with a mobile front end in the works.

In addition, I have bought and paid for real life goods with my earnings in the Steem ecosystem.

So, as you can see, these are some of the applications of a chain that is actually active and has engaged users, actually using the applications afforded to them by the chain. It is a flexible chain (that is already listed on major exchanges) that is fast exploring it's application beyond its original blogging birthplace.

It is a chain that can't provide some of the solutions that some of the more specialised chains can provide, but it one that is already showcasing (in use!) some of the vast possibilities of a chain that is both flexible and battle tested (both in usage and at market).

You can find me as @bengy on Steem.