Ajax is a big buzzword right now and something that while extremely cool can also create usability issues and headaches for the users. I’m using Krugle as the example, not because they’re the worst offenders or even bad but simply because I’ve been using them quite a bit lately and am familiar with their interface.
Let’s start with the “in-browser” pop-ups (i.e. the login). While this is a slick way to present a form to a user without a page reload, it is not visible to the browsers for pre-populate from my username/password cache so I have to type in my own username and password. Yeah, I know I’m lazy but that’s the behavior that I’m used to and it really does save me time so why take it away??
Add to this the fact that there’s not any “Remember Me” type functionality to persist this info between sessions and what do you get?? I’m not going to be logged in 99% of the time. Any functionality that requires this will basically go unused and any tracking that they might want to do regarding my usage of the site become a much bigger effort. SIDENOTE: Actually, Krugle doesn’t even persist your login between page views so if you navigate to another site and then return later in the same session, you have to login again. *sigh*
Pretty much any Ajax type web application suffers when it comes to the back button. Things to mitigate these issues have been dealt with in depth elsewhere so I’m not going to go into it other than to mention it since it’s direction relevant to my last point.
Like I said before, I don’t want anyone to think I’m down on Krugle – I’m not. I use them daily and they have been very responsive when I contact them about issues/suggestions. They’re doing a good thing!! I simply used them to point out some of the issues that using Ajax in your interface can create.