In my junk folder in hotmail some emails have started to come throu with a blue arrow next to them, its pointing down, what does it mean?

It isn't all of them, and I haven't opened or replied or forwarded them.
what does blue arrow on envelope in hotmail list indicate?
In one hour, I got 42 junk emails that had a little down-pointing blue arrow right before the unopened envelope.  Five other junk emails did not have the arrow.  This is the first time I've seen this.  Is it new?  Does it have some meaning I missed?  Thanks