Thanks for a great explanation giantcontessa.
I'm a programmer who has been trying to become a better writer (I'm barely adequate at best). On the subject of "simile, metaphor, and analogy" there are a great deal of really horrible, though very authoritatively presented, explanations out there.
I researched, and wrote my own blog entry about it, in an attempt to simply sift through everything that was out there. For me, the key to sorting it all out, was to find the explanations that were self-consistent. Your explanation meets this requirement.
Most of the blog-entries on this had simile right, though often resorted to the "rule-of-thumb" syntactical explanation you have alluded to above. Less had metaphor right, often just explaining it as some mysterious word for "expanded simile". Finally, almost nobody had analogy right. One blog simply quoted the wiki article, which in turn, was nothing but a shameless list of Sokalisms (hard to believe, i know).
Thanks for the clarity, and for being self-consistent.
The following probably doesn't make it clearer. Really just having some fun and hoping you will not be able to resist correcting my understanding if you notice it's wrong.
Start with a "rule-of-thumb" simile:
His love for her is like the fires of Centralia.
Let's also use another simile and say:
The phrase "similar to" is like the word "like"
Now, let us use this simile (metonym?) metaphorically to re-state our first simile:
His love for her is similar to the fires of Centralia.
Why isn't this a simile?