With the advent of the internet, crowdsourcing and communities, many ways to help astronomers worldwide to obtain and analyse data have been proposed; from the comfort of your own home or office, you can make a difference by contributing online. I've seen a couple of interesting ways in which to help that anyone could do. Two examples jump to my mind:
SETI (Search for Extraterrestrial Intelligence) is a scientific area whose goal is to detect intelligent life outside Earth. One approach, known as radio SETI, uses radio telescopes to listen for narrow-bandwidth radio signals from space. Such signals are not known to occur naturally, so a detection would provide evidence of extraterrestrial technology. Radio telescope signals consist primarily of noise (from celestial sources and the receiver's electronics) and man-made signals such as TV stations, radar, and satellites. Modern radio SETI projects analyze the data digitally. More computing power enables searches to cover greater frequency ranges with more sensitivity. Radio SETI, therefore, has an insatiable appetite for computing power.
Previous radio SETI projects have used special-purpose supercomputers, located at the telescope, to do the bulk of the data analysis. In 1995, David Gedye proposed doing radio SETI using a virtual supercomputer composed of large numbers of Internet-connected computers, and he organized the SETI@home project to explore this idea. SETI@home was originally launched in May 1999.
From Wikipedia Galaxy Zoo is an online astronomy project which invites people to assist in the morphological classification of large numbers of galaxies. It is an example of citizen science as it enlists the help of members of the public to help in scientific research. An improved version—Galaxy Zoo 2—went live on 17 February 2009. The third iteration of the project, launched in April 2010, Galaxy Zoo: Hubble, used Hubble Space Telescope survey data. The fourth and current version was launched in summer, 2012, incorporating new images of the Sloan galaxies and images from Hubble's CANDELS survey. Galaxy Zoo is part of the Zooniverse group of citizen science projects.
What other online alternatives do you know of and which one do you think would be a bigger contribution?