Services like yfrog, YouTube, and gist.github.com can be displayed in the right sidebar of New Twitter, if a user includes a link to them in a tweet.
Is there a place where I can see a list of the services that are supported by this sidebar extension?
There's nothing built into Twitter itself.
There's a service call Bettween that offers this. It's a little slow the first time you use it, but claims it's quicker for subsequent visits.
Additionally this post on Gamblz from 2008 lists 5 ways to find and track conversations using 3rd party applications. I don't know whether any of these are still working.
I would like to be able to add users to a twitter list without loading a separate page to find each user. So I would like to avoid going to their user page, but I'd also like to avoid having to load a page of search results (whether on twitter.com or on an external app) each time, as well.
Best Answer
I've seen a couple different lists for this.
Twitter list of photo/video supported sites: Twitpic, Flickr, Yfrog, Twitgoo, Plixi, YouTube, Vimeo, Twiddeo, Ustream, Justin.tv, Twitlens, Tweetube, Twitvid
TechCrunch Article: Dailybooth, DeviantArt, Etsy, Flickr, Justin.TV, Kickstarter, Kiva, Photozou, Plixi, Twitgoo, TwitPic, Twitvid, USTREAM, Vimeo, Yfrog, and YouTube