CHtml::ajaxLink(), CHtml::ajaxSubmitButton() and similar methods are great, but if they are located inside a portion of the page that is already loaded via ajax something bad will happen, something you may even not notice if you are not using tools like firebugs: the sent ajax requests will multiply themselves.
It's common to see users wishing to make substring DB queries, using the % metacharacter used to match anything; in this FAQ we'll search the tbl_comments table from the blog tutorial hoping to find the text in $match in the content column
I've seen many tickets regarding how to show friendly delete confirmation using CGridView's CButtonColumn in ajax request. If you are using relational database, after producing CRUD functionality when you try to delete a record in ajax mode which has child record it can't be deleted and you can see the ajax loader forever. By this way you can't show the users if a record has been successfully deleted or if there are some problem in flash style (setFlash() / getFlash())
Here is a step by step To-Do list for Yii beginners. The list is an advice of what tutorials and documentation you can walk through to get a full understanding of the Yii Framework. These can be a help to learn Yii.