Well, someone was able to photoshop the boarders of the teasers so that they are shaped like this:
Notice that the symbol appears to be dragon like? Well, there's a certain super-villain whose origins are tied to dragons. The Mandarin. In fact, Marvel.com has
this article talking about his return in Invincible Iron Man #500. Note this particular paragraph:
If you click on the word "fear" it takes you THIS:
http://marvel.com/videos/watch/1661/fear
Also, anyone remember this "timeline" from Avenger #5?
http://www.richlovatt.com/wp-content/uploads/2010/09/1284757544.jpg One of the words on there is "Fear without man" and notice what is closely linked to that--a circled "What is in the Rings?" Who do we know in the Marvel Universe who has rings? The Mandrian again.
So my guess? I think that these scenes (symoblic or otherwise) of what will eventually happen if things in the present day (in terms of the Marvel U) are not resolved. And that there will be events which transpire, some more orchestrated than others, that will lead the world to the brink of an Armageddon in which the Mandarin takes the opportunity to take over the world. Perhaps it also ties into those Tripods and the Ultron War as seen in Captain America: Reborn and Avengers 1-6