Yahoo has launched a Web-based version of its instant messaging client, at webmessenger.yahoo.com (News.com story). It's a slick Flash-based app, and it's a comfortable messaging environment for people used to the downloadable app. The Web version doesn't give you access to all the bells and whistles of the app, such as access to the plug-ins and integrated voice chat, but it handles the basics well enough.
Like Google and AOL's Web-based instant messaging services, the big advantage is that Web-based chat apps don't require a download, so you can chat on locked-down corporate machines or on a computer you're renting from a kiosk or borrowing from a friend.
The Yahoo Web app has a history feature, and a search function on top of it, so you can find chat contents from previous discussions. However, it only archives chats from within the browser app, so if you switch between the downloaded app at home and the browser chat elsewhere, your history will be incomplete.
Although it's very simple to use and has an attractive interface, the online version of Messenger is not as flexible as the multi-IM Web app Meebo. Unless all your online buddies are on the Yahoo network and Microsoft's IM network, which Yahoo also supports, it's hard to recommend Yahoo's more limited offering. If you have a friend or two on Google or AOL, Meebo is what you really need.
I like this app well enough, but what I'm really waiting for is the global rollout of the integrated e-mail/chat app Yahoo promised us back in November.