At work, it's usually just the architecture-themed blogs I look at, but even those are beautiful.
(Via ArchitectureBlog)
I signed up for Tumblr Dec 17th 2009 (yep, actually went & checked), & until recently was pretty sure that apart from those on it & other slightly-geek-about-new-things-on-the-internet people knew about, but if the recent press it's been getting is anything to go by, it's just getting bigger & bigger - which, in this case, definitely means better... *Note - when I can find online copies of the articles that have mentioned Tumblr, I shall update this post!
In the meantime;
An awesome 'I heart Tumblr' blog post
And a few of my favorite, random pictures from the site itself:
Oh, apart from the occasional bits of text, there are some amazing links too -
Enjoy! ♥