It will remain online for the forseeable future!
Minehost.org was started in 2010 to host Minecraft servers. It offered hosting based on really good hardware running at SoftLayer, which has great network performance. It was more expensive than some companies, but hundreds of people thought it was worth it, because it was rock-solid. Minehost closed its doors in September 2012. No further clients can be hosted at this time, and it's unlikely that the company will resume operations.
Minehost was well-known for giving people dedicated IPs. If you typed in your server name - e.g. public.minehost.org - Minecraft would connect directly, and you wouldn't have to remember a port number, or expect your players to. A few months before Minehost closed, SoftLayer informed us that they would be unable to continue leasing us enough IP addresses to continue this practice. They did this without prior warning, just after we had ordered a new machine, and they refused to reconsider their position. In an attempt to compensate for this, we added a shared IP feature to our hosting plans that would allow customers to pay a dollar less per month (our cost) to have a shared IP. Unfortunately, only one customer signed up for this option, and asked to be upgraded to a dedicated IP within a week. We eventually ran out of allocated IPs, and with no customer demand for shared IPs and a brand new machine sitting almost totally empty, it became clear that our position was untenable. We attempted to get Mojang to implement a DNS feature that would've allowed us to offer shared IPs without having to worry about port numbers, but we weren't able to get their attention.
We had a peak usage of hundreds of simultaneous users. Our servers had fast processors, solid-state drives, Mumble voice chat, customizable server homepages with world maps, and excellent, lag-free Internet connections. We were quite close to profitability. It was very difficult to shut down, but there was no better alternative.
The public server - public.minehost.org - is still open, and will remain so for the forseeable future, although it will not be updated frequently. This is because of difficulties with Minecraft's community-developed plugin system. At the time of writing, the most popular community-developed version of the server - Bukkit - does not have a stable application programming interface (API). As a result, plugins have to be updated by their developers, or they will eventually break when some new version of the server has a change they can't compensate for.
Normally, APIs are supposed to remain largely stable, and to gracefully handle unsupported new features - for example, if there's a new mob type the API doesn't know about, it will notify you that it can't handle it, and go about its business. Because Bukkit's development hasn't followed that pattern, many older plugins have stopped working.
Bukkit developers work for free, and their work is highly valuable. We don't wish to minimize the value of their contribution, which is huge. Certainly, Bukkit played a large part in what made Minehost appealing to so many customers and their players. However, plugin developers also work for free, and they often lose interest in keeping their plugins up-to-date because new versions of the server tend to break existing plugins. Hopefully, the Bukkit team will find a way to make this better in the future.To our customers and players, who spent so many thousands of hours building (and blowing up) worlds on our servers - Thank you. Perhaps we'll meet again someday.
By the way, several people on LinkedIn from countries other than the USA are claiming to be MineHost employees. They may be employees of some other company called MineHost, but they are not and never were associated with this MineHost. There do appear to be companies in other countries that are using the name. (No, they didn't ask.)