I was introduced to Wall Wisher last summer during an Abydos Writing Institute. Our homework included reading a chapter in our Abydos book and then summarizing what we read. We then were asked to share the most important piece of our summary by adding it to the class wall. In terms of skill, it forces students to explain themselves in a concise manner. Not only so, but we had to decide what information was most important within our own summaries.
It could easily be taught in the exact manner as explained above. While this skill and activity can certainly be achieved using a good ol' sticky note and the bulletin board at the back of your classroom, there are multiple benefits to adopting wall wisher: it's more accessible to kids, and they're more likely to view and discuss others' comments as they appear on the wall. And they're not crowded around the back bulletin board all reading each others' work and bumping into each other, being disruptive, etc. And you can save it all in one place on your computer rather than have bundles of sticky notes swimming around in your briefcase.
When Garcia-Wheeler used this in her classroom this year, however, she did say that sometimes the network would not respond and kids couldn't access the wall. In which case, you can just revert to the "old school" sticky-note-bulletin-board-procedure and try again another day.
I have heard of Poll Everywhere a number of times at both district trainings/professional development days and at the National Council for Teachers of English annual conference in Chicago this past November. Everybody basically raves about it. It's a great way to invite your kids to use their cell phones in class for educational purposes (I know, risky for some people, but I have no qualms about it). Polls are so easy to set up, and the kids enjoyed seeing the real-time results pop up on the screen as their answers were submitted and counted. If you are scared of using the ActivVotes or ActivExpressions (or don't have them registered), use Poll Everywhere instead and simply have the kids use the iTouches from the library. Kids can submit their responses either via text message on their phones OR through the internet (hence, use of iTouches). Problem with submitting via text message from a phone: polls will only accept one response from each cell phone number, so kids can't share devices if their neighbor doesn't have a cell phone. But you can submit all the responses you want via the internet (just go to http://PollEv.com, type in a response in the box that pops up, and hit "Submit.")
Here's an example of one Poll I took in my dinky 6th period (10 kids total) class- I was trying to see whether the class generally understood the definition of Imagery. Clearly we needed to revisit the term.
Also, here's a really helpful explanation of Poll Everywhere (that includes its great uses in the classroom!) on Alan November's website (no need to reinvent the wheel if Alan's already done it!): November Learning on Poll Everywhere