Community Indexing Projects
Both FamilySearch.org and Ancestry.com have community indexing projects where volunteers all over the globe can contribute to the indexing effort. This distributed "share the work" concept leads to indexing millions of records in a short period of time. For example, the indexing of Illinois (midwest region) naturalization cards took less than a year. Another example is the 1940 US Census which took about six months.
Volunteers are sent images of documents to their home computers where they enter data on their computers as well. The data is then sent back to the host for inclusion in the final index. The quality of such an index should be good because different people index the same image. When there are discrepancies between entries, an arbitrator looks at the record and decides what it should be. What if the arbitrator is wrong?
If the arbitrator is wrong, that record may be "lost" because we don't know how the data is now rendered and is not what someone thinks to look for. Recently, I had a batch of St. Joseph County, IN marriages to index. While the groom surname was clearly Grzelak, the arbitrator changed it to Grzeleck. Today I had a batch of World War I Draft Registration cards to enter. The name was Albert Qrzysciaq. It will be curious to see what the arbitrator does to that record. If you say the name, it sounds like Krzysciak. Indeed the signature of the man is spelled Krzysciak. I entered it as Krzysciak because Qrzysciaq is just silly. His birthplace looked like Tuimdiq Lemanova Galatia. This is probably supposed to be Tymbark, Limanowa, in Galicia. Since I don't know that for sure, the only thing I felt confident of was to change Galatia it Galicia.
Is there a way to get an index record corrected when you know it has an error? FamilySearch.org, lets you correct index entries of records they have imaged and let you see. This is not as easy as it should be since they make you highlite the names on the image. That takes a lot of time if there are multiple errors on the same image (and often there are). Then there are records that are indexed but which don't have images you can see (Cook County, Illinois records, for example). They do not let you correct those names at all. At Ancestry.com, you can annotate an entry but I don't know if it becomes a searchable entry (making the "lost" record findable).
If you have not done indexing before, pick an easy project that looks interesting and get started. The batches of images you are sent are arbitrary. For example, I would have preferred to work on Chicago records and particularly in Polish neighborhoods but I never got a single image from Chicago.
One thing I'm not happy about with these projects is that while the created index is open to the public (yea!), accessing images of the document may require payment (boo!).