I got this text box on one of my admin pages. Employees enter text in here, save it and it's displayed on the web page.
Now I teached them basic html (bold, undeline, paragraphs), so they can format their text.
But after they try to save text containing html, the page throw out an error saying:

Code:
A potentially dangerous Request.Form value was detected from the client (overview_en="<b>A QUALITY LEADER<..."). 
Description: Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted. This value may indicate an attempt to compromise the security of your application, such as a cross-site scripting attack. You can disable request validation by setting validateRequest=false in the Page directive or in the configuration section. However, it is strongly recommended that your application explicitly check all inputs in this case. 

Exception Details: System.Web.HttpRequestValidationException: A potentially dangerous Request.Form value was detected from the client (overview_en="<b>A QUALITY LEADER<...").
uuuh...ok...whatever