For a recent IA project I have been using an online wireframe application called Hotgloo.  I really enjoy working on Hotgloo but as an online application there are pros and cons.

Advantages

Interactivity – You can create interactive wireframes at ease.   A number of options like drop downs, input fields, radio buttons are pre-created and can be used to represent interactivity.  Your design can also be enhanced by inserting images but also adding internal and external links as well as pop-ups with messages.   Your team, your client, even the end users can interact with it and give insightful feedback.

Share – It allows to create a preview link and share it with your clients without being added to the account.  Instead of sending documents;pdfs or other formats, woring about the file sizes, Hotgloo allows you to send across just a link.  Clients can preview the project on a browser and your wireframes can be as realistic as possible. The link can also be send to end users for testing.

Collaboration – You can add users on your projects with different priorities.  Admins and members can access the project at the same time.  Members can preview the project and add or edit comments.

Accessibility – Hotgloo projects can be accessed online any time, from office or not without installing any software.

Learnability – It is enough to watch a few of the provided videos and start playing around with Hotgloo.

Version Control – There is the option to save different versions of your projects and back up different stages of your work

Auto-save – Hotgloo autosaves your work every few seconds.  Even if your browser crashes you will not loose your latest amends.

Drawbacks

Reliability – I noticed a few times that some of  the functions, features and styling didn’t display properly, so extra time was needed to amend or recreate them.

Heavy – Hotgloo uses flash. If your computer or internet are slow you will probably not be as productive as you would like to be.  Unfortunately it has crashed my browsers a couple of times.

Back up – Although it is online and you may think that a back up is unecessary, to me it is always safer to have a back version on my computer.  There is no option to back up your project so your work is totally relied on hotgloo and internet connection.