There is an interesting website service called ThingSpeak (link). The website uses a simple protocol, so simple that even small micro controllers can use it, to collect data and then display the data in handy graphs. Up to 8 parameters at a time, once a minute can be posted to the site, where it is logged and then graphed.
I’m using it right now for the solar power weather station. I’m posting the temperature, humidity, and the voltage of the battery and solar panel. So far it’s been really helpful in debugging the solar weather station as I can let it collect data and the next morning take a look at the graphs to see how much energy the weather station used overnight while the battery can’t be charge by the solar panel.
The graphs of the solar power station can be found here.
As well as collecting data and displaying graphs, there are other features such as acting as a proxy to do more complex web requests, doing actions based on collected data, etc. All this wonderful stuff for free. I’m not sure I understand the business model, but the site is really useful and easy to use.