Over the weekend, I found myself working on a machine that had no Twitter client installed, and I'd just had a donut and needed to Tweet that fact. (I kid, Twitterati; I'm one of you!) I could have gone to twitter.com but instead I decided to load up Seesmic's web-based client, which I wrote about last month. I was pleasantly surprised to find that a lot of progress has been made. I wound up using it all weekend and quickly became attached to a few of the new features.
Most notable is support for previewing (some) shortened URLs. This still depends on which shortener is used, with bit.ly apparently being a Seesmic favorite. Some of the stand-alone clients also offer previews, but what I like about the Seesmic web browser is that no click is required. Roll your mouse over a link and you get more info in a popup. For links to web pages, you'll see the full link, and (sometimes – it seems to depend on the destination) the page title and description. For images (twitpic, yfrog, mobypicture) you'll get a small version of the image in the popup, but best of all, if the link is to a YouTube video, a tiny version of the video opens in the popup. Click on it once to start playing it, a second time to open the video in another tab/window.
Another nifty new convenience feature is auto-loading of more tweets as you scroll down to the bottom of the pane. Depending on the speed of your connection (and Twitter) you'll barely see the "More" button before the web-client loads another batch of tweets on its own. The panes themselves scroll quickly via mouse wheel without requiring the use of the scroll bars.
A new Favorites pane has been added, and clicking a hashtag now opens up a Search pane with a search for that hashtag loaded and ready to go.
On the downside, there's still no support for Groups or multiple accounts, but given that it's only been about a month since the client launched, they've made great progress. There's a feedback form on the Seesmic website, and both of these features are tagged as "Planned" on it, so hopefully we'll get them before too long.
All in all, the Seesmic web client is quickly becoming powerful enough to completely replace stand alone Twitter clients for all but the most hardcore Twitter users. And of course, it is free to use (though I assume that at some point Seesmic will have to find some way to generate revenue from it). Definitely worth checking out.