Alex Bosworth posted a list of places where Ajax should be used and where it should not.
Just the basic list here, head over to Alex to read the details:
Here are places Ajax should now be required in a web application:
- Form driven interaction
- Deep hierarchical tree navigation
- Rapid user-to-user communication
- Voting, Yes/No boxes, Ratings submissions
- Filtering and involved data manipulation
- Commonly entered text hints/autocompletion
Here are some places Ajax shouldn't be used:
- Simple forms
- Search
- Basic navigation
- Replacing a large amount of text
- Display manipulation
- Useless widgets
I currently can't think of any obious disagreements to his points.