As I was struggling along searching for one of Fred Gerner's brothers last night I was thinking how hard it is to know if this John or that John might be Fred's brother. How could I even guess which one might be the right one so I could do further research? In the absence of family records, census records are my best first resource. In this situation, their biggest help may be that they recorded ages.
I'm feeling particularly grateful to whoever came up with the idea for indexing census records and grateful for those Works Progress Administration (WPA) employees who so carefully cataloged and recorded each individual name on cards. I'm thankful for Robert C. Russell and Margaret K. Odell who created the Soundex system, that phonetic algorithm that indexes names and allows us to find them in a census. The Soundex is not as commonly used now as in previous decades but it provided my very first acquaintance with genealogy research in the census.
I'm thankful to more modern indexers at FamilySearch and ancestry.com and all other companies whose work allows us to more easily find an ancestor who might otherwise be lost in a sea of records. Imagine having to search a census page by page to find an ancestor. I've done it but rarely need to and I'm grateful for that.
I'm grateful for electronic devices which make document images available online and for download. I'm thankful for computers, scanners, and computer programs which make record-keeping of documents pertaining to and photographs of my family organized (somewhat -- at least as far as I am organized) and more easily accessible to me. With a few clicks I can look at the census record of my great-grandmother and with another click or two, look at her photograph.
Sometimes I take things for granted but just now, I'm very thankful.