30. July 2007 08:11
The Gravatar is a fiendishly simple idea; register an image with your email address, and that image is displayed in the comments of (supporting) blog software. A nice easy way to maintain a visual cue on who people are, and who's talking when in the conversation.
But if you haven't registered a gravatar, what then? Normally, you get a blank image, but you can supply a fallback redirect url with your gravatar link.
Phil Haack and Jon Galloway created an HttpHandler implementation of Don Park's Identicon idea - a way to generate abstract geometric shapes based on an IP address. And of course, used it as the fallback to the gravatar image.
But if that's just a little too abstract for you (and since it's based on IP address, not permanent), you could always use a MonsterID, which is the same sort of idea, but based on the same MD5 hash of your email adress that gravatar uses, and displaying, well, monsters. (More examples and details are on the announcement page than the project page. And here's an alternate template, but I can't find a download link.)
So that's comments sorted - what about trackbacks? Well, you could use a WebSnapr thumbnail, but that might be just too small to be any use, so how about a favatar? (That's an avatar taken from the favicon of the website sending the trackback/pingback.) There doesn't appear to be a .net implementation, but it shouldn't be too hard.
Now all you need is a server side cache of some sort so that you're not continually regenerating all these images (and proper etag handling for client side caching)...