 <p>Obviously Google are major users of Grid Computing; all their search service relies on it, and many others.</p> <p>Engines such as BigTable are based on using lots of nodes for storage and computation. These are commercially very useful because they're a good alternative to a small number of big servers, providing better redundancy and cost effective scaling.</p> <p>The downside is that the software is fiendishly difficult to write, but Google seem to manage that one ok :)</p> <p>So anything which requires big storage and/or lots of computation.</p>