Earlier in the week we quietly updated Popfly. Why quietly? Because we really didn't add any new features. We fixed some bugs, sure, but mostly what we did was roll out an improved caching system. Between the middle-tier cache and changes we made to take better advantage of the browser's cache, we're seeing anywhere from a 2X to a 6X performance improvement when you load an existing mashup. A lot of this work is in CacheMan, which Sriram (a dev on our team) implemented as a personal project and which turned out to be useful in Popfly.
I waited to post about it mostly because... Well, mostly because I'm lazy. But also because caches are among the most complicated things to get right. Caching -- especially multi-level distributed caches -- are very finicky. I'm happy to say that this one is working. At least for now.
You should notice that your embedded mashups like the one on Soma's blog or the one on the Express download page should load much more quickly. Even more quickly if you refresh the page.