The concept behind the WifiDuino, I think, is to provide a low-cost, very small, Arduino-compatible single-board microcontroller with wifi capability (and an optional 128 x 64 OLED display). At this point the WifiDuino is a recently-launched Indiegogo campaign, not an immediately available electronic component. The 'early bird' Indiegogo cost to support this campaign is $29 for the WifiDuino unit. If you want the WifiDuino with the small OLED display, the early bird support level for that perk is $44.
For people not familiar with Indiegogo campaigns, when you pledge the $29 or $44, you're not 'buying' a WifiDuino. What you're doing is giving the person or project team who launched the campaign a specified amount of money with the expectation that if the project is successful, your monetary contribution will get you whatever the specified perk was for that level of contribution. With Indiegogo, Kickstarter or many of the other similar crowdfunding or crowd-supported project websites, you always run the risk that you'll contribute the amount of money you've chosen and end up with nothing, or with an item that doesn't work or is not quite what you expected.
I don't know enough about microcontrollers yet to know after reading the article whether the WifiDuino would be a useful and cost-effective item for microcontroller projects that need wifi capability. At the next meeting of the Humboldt Microcontrollers Group, on June 12, I plan to ask whether the other people at the meeting think the WifiDuino looks like a good deal, or if they know of better options to achieve the same capabilities.
After looking at the Indiegogo website, I did a bit more online research related to the WifiDuino. On the Indiegogo page for this project, it mentions the Spark, another small Arduino-compatible device with wifi capability. The Spark Core was another crowd-supported project. It was on Kickstarter a year ago, and it was wildly successful. They asked for $10,000 for the Kickstarter campaign, and they raised $567,968! The WifiDuino project still has more than a month to run (so support it if you like the looks of the project), but so far they've raised only $5855 of the requested $23,000. It's impossible to say if their Indiegogo campaign will catch fire and be successful, but I hope it will. Projects like this are helping drive innovation in the Arduino world in much the same way that Arduino helped catalyze innovation in the microcontroller world.
Two other options for Arduino and wifi are to use, (1) a standard wifi Arduino 'shield', like the Adafruit CC3000, along with an Arduino Uno, or (2) to use something like the Lantronix xPico WiFi Shield for Arduino that I saw in a recent EE Times article.
The brief online search and reading I did tonight showed me that wifi and Arduinos is yet another microcontroller topic about which I've a lot to learn. One step at a time...