I know SA means the same license applies to remixed works. But what does that really mean? Can someone give me an example?

A fictional example is fine.

Answer:

Suppose you took a photo and publish it under CC BY license. If someone uses it on an article and references your photo properly, the article can have any license because it’s not an adaptation/remix of your photo, the article just has your photo inside. If you publish the photo under CC BY-SA license, the same applies (in this case, the reference to your pohoto in the article will be slightly different).

Now suppose that you publish your photo under CC BY license and someone makes and adaptation/remix of it. For example the new work is your photo cropped and with some filters applied. The author of the adaptation can add the NonCommertial clause to the derivative work. He/she can license its new work with CC BY-NC license or with CC BY-NC-SA, stopping any commertial use of the adaptation and if he/she wants getting paid for any commerdial use.

But if you publish your photo under CC BY-SA license, this is not possible. The adaptation of your photo must use the same license. The remix, the derivative work, must be CC BY-SA too! To make any other use, the adaptor needs your permission.

Did I explain myself?

You have more info in the Creative Commons FAQ:

• What is an adaptation?
• Can I combine material under different Creative Commons licenses in my work? (take a look to the compatibility table)
• If I derive or adapt material offered under a Creative Commons license, which CC license(s) can I use?