Online providers of image data need to make it clear where those images were obtained. Any documentation contained in the records needs to be contained in the website created by the online provider. Users need to know where images were originally made. We should take whatever we're being given and "be happy that we have anything at all."
Microfilm copies of actual records usually have a cover sheet or page that at the very least explains the holder of the records. In some cases there may even be more detail in a sheet or two of explanation that was microfilmed before the actual records.
Others have made eloquent arguments that consistent citations need to be created by Ancestry.com, FamilySearch, and others that provide access to digital images of original records. I agree with those sentiments.
We also need information on the provenance of the records, precisely who had the records that were digitized and if there were any caveats about those records.
I used a set of Tennessee marriage records for a Casefile Clues article. The records were on Ancestry.com and came from microfilm at the Tennessee State Archives. That is as specific as Ancestry.com got about the source of the records. Searches for specific individuals took me to specific pages in the apparent books, but it was not possible to move the images to get to a "title page" or "cover sheet" as one can on microfilm. If there was a sheet or two of background information, I did not see it. If the cover of the actual book was filmed (as sometimes is done) I did not see it.
I had no clue where those Davidson County marriages came from. Most likely the county.
Why does it matter?
Because it appears that the records I was using on Ancestry.com's digital images were handwritten transcriptions of the originals. I cannot be certain, but the handwriting was very consistent and the pre-printed form just did not look like late 18th century. But I could be wrong. The problem is that there is no way of telling.
Does it really matter?
Yes it does. The names in this family are slightly unusual and an untrained eye could easily misread Hettie for Lettie or Lottie, etc. And in families where several brothers are in the same area, resulting in thirty first cousins getting married within fifteen years of each other details matter.
Not only am I calling for better citations, I'm asking that vague statements about the origin of images be replaced with meaningful statements.
I'm glad Ancestry.com is indexing records and linking them to record images. It saves me time. What doesn't save me time is when I have to hunt down the probable source of that image.
I'm grateful for the indexes we have at Ancestry.com and FamilySearch. What I'm not grateful for are those record sets where the actual source description is vague. I should not have to try and reverse engineer where the records came from.