Is it ethical to host ads on an institute provided homepage?

It may depend on the rules of your institute, but I'd bet that putting ads on your homepage is not allowed. You should certainly not put up ads without verifying that you have official permission to do so.

If you work at a public university or other governmental institute, then putting up ads could be considered using government property for personal gain. That's probably not just unethical, but illegal (but you'd have to look into the appropriate laws in your jurisdiction to be sure).

If you work at a private university or institute, then it may not be illegal, but there are still probably institute rules against using institute property in this way. I'd be surprised if any big organization didn't have such rules.

This is a matter of institutional policy. Find your university's IT policy and read it; if advertising isn't explicitly mentioned, ask someone.

• Here is an example of an advertising policy, from the University of Florida. It permits only a limited group of university offices to place advertisements on their sites.
• Here is a policy from Florida State University and another one from the University of Greenwich that forbid advertising.
• Here is a policy from the University of Aberdeen that permits advertising under certain conditions.
• Here is one from the University of Nevada, Las Vegas, that generally forbids advertising but makes an exception for advertising academic endeavors - for example, a faculty member linking to a retailer or publisher of the academic book they have authored.

The point is: check your university policy.

In academia the goal is to build one's scholarly reputation. While this is done primarily through publishing quality research, developing a professional network is also important. Ideally one's webpage is:

• a summary of your research,
• a repository collection of useful links,
• technology tips you want to save,
• projects you have started,
• printed on your business card, and
• (most importantly) a portfolio of your work.

When I visit a colleague's tidy web page, my impression of her goes up. Ads would erode this perception in exchange for a few dollars.