There has been much debate as to whether or not blogs, tweets and the like achieve anything concrete. I believe that they can be very effective in a number of ways, as I mentioned in this article in the Institute of Physics magazine, Physics World.
Regular commenter Ian, aka Laurasdad has suggested I mention a very effective example of the power of blogging. The science blogger Frank Swain (SciencePunk) recently described finding an undeveloped film in an old camera he brought, and featuring mystery images from the film in the blog post. Before long, commenters were adding information that began to fill in the facts behind the mystery of the grave shown in the rather spooky shots. Another SciencePunk post fills in the (unsolicited) detective work that arose from his blog post.
As Ian comments:
I know about SETI and harnessing the power of down time on PCs and I know that the genealogical forums can turn up all sorts of stuff on ancestors but for something so trivial to get solved so easily made me wonder whether there are other solutions for business problems or for (maybe) police/national intelligence. It depends on having a critical mass of users with that particular interest; the question is how can you tap into those users with an interest and time on their hands ?
The SciencePunk mystery photos have demonstrated well the power of harnessing reader power, if you can provide a challenge that engages people. It's an interesting approach to researching a topic that we may see more and more of as internet communities develop.