Another tidbit from JKR's site (semi-spoiler)

[justcarol67]

> bboyminn:
> 
> Carol, I've always thought it was Eihwaz too.
> 
> Look at the definitions from another Runes site.
> 
> http://www.stevenforrest.com/runes.html
> 
> EIHWAZ:  Defense, Striving
> Although you are facing a trial, you are protected. The skill you
most need lies in trusting that protection.  Unforeseeable power and
wisdom await you if you avoid panic or precipitous overreactions. Be
strong, and judiciously bold, and no harm should come to you. This is
the Rune of TESTING.
<snip>
>While I can see ways to apply Sowilu to Harry, and admit that Sowilu
> looks more like a lightenig bolt, Eihawaz is practically a summary
of the HP series. 
> 
> Further, I do think it is significant, but I'm not sure how. Though
I vaguely remember reading JKR saying that the shape of Harry's scar
was not significant. Of course, just becaure it isn't 'significant'
> doesn't mean it can't be symbolic. <snip>

Carol responds:
Actually, she said that the shape wasn't the *most* significant thing
about the scar, not that it wasn't significant at all. I agree that
the description of Eihwaz's symbolism sounds *exactly* like what Harry
will be facing in Book 7, and I think it's significant that JKR
specifically brought the eihwaz rune to our attention by having
Hermione miss that question on her Ancient Runes OWL. I expected
either Hermione or Luna to connect the scar to a rune in HBP, but HBP
trampled on almost all my expectations, so naturally it didn't come
through on that one, either.

Still, there's hope for a scar/rune connection in Book 7, and the mere
fact that an Ancient Runes book is one of the clues on her website
fortifies that hope a bit, at least for me. And I'm sure that JKR had
Hermione study the subject for a plot-related reason.

As for the Potterverse number runes that the book actually displays
(instead of the standard runes that Hermione apparently studied), I
don't have a clue what that's about. I think it was just a bit of fun,
a riddle for the kids to figure out and the grown ups to cheat on. (I
did about half and half.)

Carol, who would have liked to know the meaning of the runes on DD's
Pensieve even though it's probably not important