Practical, scalable solutions need to be found, such as those outlined by Regina Reynolds in her excellent paper. Michael Kaplan is on target with his concept of a core bibliographic record enriched with contributed data from a number of sources, including publishers and vendors. So aggregations are very much here to stay. The nature and size of aggregations can vary widely, in content, coverage and business model, so that it is difficult to deal with a uniform set of processes or standards for bibliographic control of these collections. One title can be part of multiple aggregations, which only exacerbates the multiple version problem.
Titles move in and out of aggregations, often without notice to the aggregators themselves.
These records also need to be maintained, updated, deleted, etc. And, regardless of the source of the record, we need standards and some agreed upon level of quality enforcement. Current methods of handling access to aggregator titles vary widely from library to library. Some offer no access to the individual titles, but simply a record for the aggregation itself in the OPAC - hardly a satisfactory solution. Others offer a web page link to the aggregation.