Recently, WorldVitalRecords.com kindly sent me a complimentary subscription. I have used this website for the past few years off and on, but found, like other sites that the search engine was so poor that rarely did I find anything productive. So, in response to the free offer, I decided to explore the website with a few searches. To my surprise, since MyHeritage.com purchased the site, it has been redesigned and functions much more efficiently.
My first search turned up links to records that I immediately added to my ancestor in FamilySearch.org's Family Tree program. The sources were not unknown to me, but having them organized in a list, gave me the incentive to add them to my Source Box. By the way, I am finding having the Source Box a great way to gather information off of the Internet without using an intermediary program like Evernote.com or Dropbox.com.
Back to WorldVitalRecords.com (WVR). I began searching for my immediate known relatives. The purpose was to see what kinds of records I might find compared to those I already knew existed on the Internet. First, WVR has a convenient link to FindAGrave.com and my first efforts had links to that website for the people whose names I searched. The program found both the headstones for my Grandfather, LeRoy Parkinson Tanner. I also had a link to 9 MyHeritage.com Family Trees, including my own, most of the others turned out to private and gave no further sources.
Moving back two generations to my Great-great-grandfather, Sidney Tanner, was more productive with a reference to an obituary in the Salt Lake Tribune from 1895. Unfortunately, the image of the page never did load. I could get the references from the Utah Digital Newspaper project, but I have no explanation for the lack of images. The newspaper images in WorldVitalRecords.com are supposed to be coming from the NewspaperARCHIVE.com.WVR had a link to Pioneers and Prominent Men of Utah, including a photo. I was already aware of all of these sources, but if I hadn't been familiar with them, they would have given a fairly good start with some valuable sources.
Both of the searches I did were of people with a lot of online presence. So I decided to move to someone from my family with few records online or at least, few that I am aware of. I moved to searching for Margaret Jarvis born in 1857 in Boston, Massachusetts. With such a common name and location, it was evident that the results, although voluminous, were inapplicable. The program did identify her in family trees, but none of the remaining results were pertinent. By specifying the location in Arizona, I was able to get more pertinent information.
It looks like WVR is a valuable resource withe a huge potential, but it will take some work to find the documents you are looking for.