Massive variability searches: the past, present and future

Many decades ago a search for variable stars was one of the main areas of astrophysical research. Such searches, conducted with CCD detectors rather than with photographic plates, became a by-product of several projects seeking gravitational microlensing events towards the Magellanic Clouds and/or the Galactic Bulge: EROS, MACHO, and OGLE. These searches demonstrated that is is possible and practical to process in near real time photometry of tens of millions of stars every night, and to discover hundreds of thousands of variable stars. A limited subset of new variable star catalogs was published, but no comprehensive database of all photometric results became public domain so far. In the last few years a much broader, but shallower searches have been undertaken, and many other are at various stages of implementation or planning. There is a need to develop a system that would allow all these data to be processed and to be posted on the Internet in real time. Full information related to variability of point sources is made of a relatively few data types, hence it may be relatively easy to handle. Yet, it may be diverse enough to be interesting to a large number of users, professional as well as amateur, making it possible to do real time virtual observing, as well as data mining.