Whoa I just got New Tumblr's top nav bar all of a sudden. Nice. Probably a lot more convenient to see the New Post button rather than feeling you need to go back to Page 1.
Note to staff:
Still though - ease up on the jQuery guys, we don't need a zillion animated cross-fading transitions, we need speed and performance and reliability. Tumblr STILL makes my laptop's fans kick in in the way that only heavy Flash sites do.
Which is partly due to content, which isn't your fault - GIFs are notoriously inefficient and can't be tasked to the GPU. But also, you're taxing the GPU with layered CSS transparency, animation and crossfade effects over the top of them.
But what you can do is not serve GIFs in the original format.
Maybe take a leaf from Twitter: When you post a GIF there, they actually convert it into looping H.264 video, which as you know is a zillion times more efficient, about 10x smaller, way more mobile-friendly for people on restricted data plans, and even a smartphone's GPU can cut through it like butter.
Yeah, means you have to build a scalable GIF-to-MP4/WebM rendering cluster, but you're smart folks and you have Yahoo! money now.
And still, when you reblog something, WHY do you need to load the Dashboard underneath the compose modal? That means the client side is loading a lot of heavy graphics and front-end code that isn't even being used half the time. Totally inefficient!
Maybe the compose/reblog code is part of the Dashboard? To me the smart thing to do is modularize that code and split it out into its own library, so that you can compose your reblog from wherever you are.
And smarter still: Make 'reblog' a choice to reblog as-is (without invoking the compose modal at all!) or reblog with comments.
Not telling you how to do your job, of course :)
Oh, one more thing: Can we have a Settings toggle to open blog URLs in a new tab rather than that weird slide-out sidebar? It's really just useless to me, so I'd like the option to disable it...