remove advertising on login page of Salesforce

If you have SSO then I assume you have My Domain enabled.

In the My Domain setup you can set the right frame URL, if it's blank it loads the ad from Salesforce. I would point it to some internal page for your users.

Or, you can create a force.com site page with any image/value you want and it would be 100% on the platform.

Or, I found there are blank website on the internet you could point to as well.

A quick google search found https://blank.org/ which is just a blank white page. In one of my sandboxes I set it and it's a white frame on the login page.

If you are using chrome, you can make a chrome extension to do this. Firefox and I think Safari also allow you to make extensions.

My extension widens the login inputs, but making the advertising div invisible should be pretty easy also.

Make a manifest:

{
  "manifest_version": 1,

  "name": "Modify CSS and HTML",
  "version": "0.1.0",
  "description": "Modifies Salesforce Login Pages",

  "browser_action": {
    "default_icon": "Your_Icon.png"
  },

  "content_scripts": [{
    "css": ["styles.css"],
    "matches": ["https://test.salesforce.com/*","https://login.salesforce.com/*"]
  }]

}

CSS:

#right {
    display: none!important;
    /*you could also try visibility:hidden!important;*/
}

Add an icon (19x19 px), put these into a folder and zip it.

Then open your extensions folder in chrome and drag the zip onto the extensions area. Chrome will recognise it and install it.

For the full login tweak example, check it out on github here

It's possible to customize the right side section, see bullet #6 in Customize Your Login Page with Your Brand:

6. Enter the URL of the file to be included in the right-side iFrame on the login page. The content in the right-side iFrame can resize to fill about 50% of the page. Your content must be hosted at a URL that uses SSL encryption and the https:// prefix. To build your own custom right-side iFrame content page using responsive web design, use the My Domain Sample template. Example: https://c.salesforce.com/login-messages/promos.html

In our SSO setup users do not have to enter any passwords, and they are not maintained in Salesforce - when user is clicking on the SF bookmark for our domain (e.g. https://mydomain.my.salesforce.com) they are logged in automatically when they are on domain, or being asked for a domain user login password served from the corporate identity provider website. Also, when they click on the hyperlink (e.g. https://mydomain.my.salesforce.com/SFrecordID) they are logged in as above and redirected to the record page.