I don't at all like people using these external family tree sites as sources. Primary sources are church and government records, first hand accounts, newspaper records, and photos.
As family tree researchers, our aim is to use these primary sources, to try and present the lives of our ancestors.
Secondary sources are government index sites and second hand accounts of stories, handed down.
Ancestry, Family Search, and others can do a great job of gathering primary and secondary documents, and are really useful tools, and it is quite ashame that it has become a lucrative market, in selling access to these documents.
But as I said above, I think our job is to provide the sources, and create the story. Not provide links to links to the source. Besides, it looks tacky. A good profile done properly, too me, looks a whole lot better than a profile with gedcom comments or ancestry links. I could give plenty of examples.
So, for the sake of making our profiles look better, please take the details from the source that you have found on ancestry, and put those details as a source on your profiles, not a link to ancestry.
Feel free to look at the profiles of any of my ancestors. I'm trying to work my way through them all, making them look like they have been done properly. I've finished going through my great great grandparents, and will be starting soon on my great great great grandparents.