"We found you new ancestors—just by looking at your DNA.
Our latest scientific innovations make it possible to discover ancestors you never knew you had–just through your DNA. It's an entirely new path to finding your family story"

This is total misrepresentation, if not outright fraud. The "scientific innovation" is just a new twist on the original gimmick - comparison of your family tree with those of folks that you match. Trying to keep this as simple and brief as possible (I think we could all write a book about our issues with Ancestry DNA):

Original product gimmick: A leaf hint is generated if the system identifies potential common ancestors by comparing your tree with your match tree.

Problems: Potential ancestors are identified by comparison of family trees, and thus dependent on the info in the trees (accuracy/quality, exact match of dates and places, errors due to common names, etc.). No information is provided as to how you are matching (chromosome comparison), so no way to evaluate if the match is valid, or if the match is actually due to the ancestors flagged with a leaf hint. Having a parent tested revealed that many of these flagged common ancestors were coincidental and not the cause of the match - e.g. you might have a match with someone sharing common ancestors on your dad's side of the tree, but that person does not match your dad.

The next "big thing": Massive purge of match lists (said to be "false positives"), and introduction of the "DNA Circle".

Problems: Although many of the matches eliminated were likely false positives (no way for us to know for sure since no chromosome comparison was ever provided to support those matches), those who had been working with known cousin groups and had uploaded their raw DNA to GEDmatch and/or FTDNA knew that many of the matches that had been eliminated were NOT false positives. (Part of the motivation for the purge may have been that match lists had become too unwieldly.) The "DNA Circle" like the "leaf hint" is dependent on info in the family trees (same issues with accuracy, etc.). Folks who don't have trees attached to their results, or have private trees, won't be included in a circle. Known cousin matches with slightly different ancestor info (name variation, dates), wrong ancestor info, or who haven't worked their trees far enough back in time won't be included in your circle. There is no correlation (chromosome comparison) of how the folks in the circle are matching each other, so there is still no way to evaluate if a match is due to a specific ancestor or ancestor pair. A person may be included in a DNA circle by matching only one person in that circle, increasing uncertainty that the match is due to the identified common ancestors of the circle (which again have been identified by tree comparison, not chromosome comparison).

Latest "big thing": The system searches for common ancestor names in trees of the members of your DNA circles that are not already in your tree. The system also searches for common ancestors among members in the DNA circles of people who match to you, but are not in a DNA circle with you.

Problems: Still dependent on the accuracy/quality of family trees. Still no correlation with how people are matching each other - the only "triangulation" being done is who matches who, not HOW they are matching. Therefore, the potential for errors in ancestor prediction is huge. As already pointed out in other posts, many of the "new ancestors" turn out to be in-laws. People in these DNA circles are very likely to have other ancestors in common that are not your ancestors.

Bottom line: Ancestors are being predicted based on who matches who, and not how they match. The fatal flaw is that the basis for all predicted ancestors is other people's trees. Knowing how bad so many of the family trees in the system are ...well, this is a nightmare for serious researchers, not to mention a major disappointment.

Recommendation as always, quit believing folks trying to sell you something but won't show you what is behind the curtain. Upload your raw DNA to GEDmatch and/or FTDNA and encourage your known cousins and other matches to do the same. Keep after ancestry to do what any reputable testing company should do, provide the chromosome comparison information to support each match.