Unfortunately their community pages are long, long conversations that are not trimmed up and easy to read. Once you find a gem of information, post it here.
Particle.io (formerly Spark.io)
This is an "Arduino-like" processor. So far it has run all my Arduino code without a problem. We even brought over some other libraries and they worked. This platform easily connects to WiFi and Particle.io runs a cloud based service that makes talking to your core easy. Once the Particle Core is on WiFi then you can compile your code for it using either a web browser or their Particle Dev application on your local computer. In either case your software is compiled in the Particle Cloud and then pushed down to your Particle Core. This is beautiful. There is no need to be anywhere near your Particle Core when you send it new software.
The Particle firmware contains libraries that let you expose a local variable on your core, or a local function. Then these can be called from any web browser. Thus you can interact with your software on your core from anywhere in the world. Lastly, they offer Spark.publish which your software can call to send short messages through the Particle Cloud service (free) to anywhere. Your own server could monitor the Spark Cloud for alerts from your core(s). IFTTT.com offers a channel for Spark. I've had my core publish events to the cloud that IFTTT picks up and turns into SMS messages to my phone. IFTTT could also add events to a Google Docs spreadsheet.
The original Spark Core cost $35 and was configured via an app on a smart phone. In June 2015 they will ship the new Photon which costs $20 and I believe will be configured via its own WiFi hotspot (like the way Chromecast is configured). In October 2015 they will ship the new Electron which will offer cellular data connectivity for $3/month. In October they are also planning to release a solar power kit for the Electron. With all of this you will be able to put an Electron on the top of any local mountain and interact with it forever. Wow.
We found a bit of code that would compile and run on the Spark Core, but not on the Photon. Here's the workaround:
You can run this from my web site, or go there and download all the code so you can modify it and run it anywhere you want. The download includes a simple sample firmware app to run on your core. But the web site also works with the factory installed firmware.
Flashing Green does not connect
My assessment: In my office the WiFi signal is strong enough most times, but occasionally someone/thing near by our house starts transmitting (perhaps the police station?) in a way that prevents my Spark Core from connecting when it is 20 feet from the WiFi access point.