Well, I took the plunge and got my stuff going into the grovestreams.com site. I did it first on the raspberry pi since I moved my house controller over to one of those little devices, then I did it again with an arduino. When I started the process, there wasn't an example for an arduino on the site, but I asked, and got an example that I could try out.
Their example worked on my first try. However, it works off a temperature probe and I was too lazy to hook one up and just used a random number instead of the probe. It worked fine for a few hours but I started noticing that the arduino was losing ram since they were using Streams in the sample. I contacted them and they came up with a different example that seems to be pretty good. Obviously it isn't exactly the way I'd do it, but it works and really illustrates what can be done.
I didn't buy into tochinets discussion of the richness of the API until I was chasing bugs in my code and it turns out that the site can do just about anything you could want for logged data. They'll even average the data so you can chart it that way. I complained about the (to me) obscure way some of the facilities are presented and they ... (wait for it) ... replied.
Yep, they actually answered my mail. This place is new and just coming online for folks like us, and they answer questions. I was told they were going to have a forum later when they have the time to attend to it and they have a very easy to follow tutorial on the arduino now.
My house is recording data there on a minute basis, and except for the occasional bug in my own code, has done fine. I'd post my code that is live, but it's in python and running on a Pi now. The arduino code I did was just to see how hard it would be to do the same thing on one of them. Obviously I have too much free time.
One of the really cool features is that I can create an alert that will send email to me when something happens. I created one based on power usage such that when my house power usage goes over 10kWh, it sends me an email. That's so cool. My house lets me know it's using too much power from a web service out in space somewhere. (I'm easily entertained). I haven't even begun to use the things they have available, and probably won't for a while.
Nope, this site ain't free. But, it looks like us experimenters can keep under the billable level with a little attention so that it'll cost us nothing to experiment and track a few sensors. It could wind up costing us if we expand to a whole bunch of stuff being logged really often, but the pricing looks waaaay more favorable than Xively went to.
One of the things that confused me at first was the huge description of organizations, components, streams and such. It took a bit to get past that. What they have is a site for things like smart toasters. You buy the toaster and when you hook it to your wireless at home, it signs into grovestreams, gets an id, and begins to log how much toast you eat. This takes some smarts on the web app because, as we all know, toasters are dumb. However, that stuff can get confusing, so I recommend first taking a look at the arduino example because that's something we understand. They also have a 'sandbox' that illustrates a lot of the features that we might want to use; recommended reading.
I don't have a blog post on my site about this service yet, but I should have later today. I was impressed.