Ann points out a very good but often overlooked part of link building in her article...

Be consistent with your "link to" urls!

Has anyone ever seen a search engine index both the non-slash and the slash version?

Seems to me they have figured out to use one or the other. Would love to see an example of them indexing both (thus splitting the link pop. as stated in the article) if anyone has one.

I've never run across it as a search engine problem before.

Jill - In my entire career Ive never seen non slash and a slash version of a folder index file indexed by any search engine - but just like I mentioned in a comment on Ann's post - there should be a distinction between folder indexes and rewritten urls - because it is possible to have two files that exist in both a slash and a non slash version that could create a "split link pop" result - but I doubt the split link pop could occur on a folder index based on a non slash and a slash

My concern is that users view domain.com/something and domain.com/something/ as identical and they aren't going to stop doing so any time soon.

Also, I've noticed that browsers (in the history bar and other functions) will gleefully strip away a trailing slash and there's nothing you can do about it. If that trailing slash is necessary to make the page work, your page will break when access from browser history, no matter how consistent you are with your URL coding and in your link building.

In a related issue, Google seems to strip away the index file from your URL if there is one. (domain.com/folder/index.html gets displayed as domain.com/folder/)

While consistency is a must, for sure, it's important to make sure your URLs work either way, whether through redirects or whatever.

I always wondered about that, good read...