Are you talking about your e-mail, or Firefox?

e-mail; Go here and register for protection for your e-mail and phones; The National Do Not Call Registry

Firefox; You may have ad / mal-ware. Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up. +++++++++++++++++++++++++++++++++++++++++++++++ Adblock Plus {web link} Blocks annoying video ads on YouTube, Facebook ads, banners and much more. Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).

Adblock Plus Pop-up Addon {web link} Adblock Plus Pop-up Addon extends the blocking functionality of Adblock Plus to those annoying pop-up windows that open on mouse clicks and other user actions.

Forum; Adblock Plus Homepage {web link}

You might try running your Firefox with the plug-in Coupons, Inc. Coupon Printer 5.0.2.5 disabled. See if that helps.

You've marked the two replies as "helpful" but is your problem solved?

Thanks FredMcD and alan_r for the suggestions. I waited to provide feedback in order to observe changes made over time.

Considering all suggestions proposed, I managed to bring the amount of targeted ads in Yahoo Mail to a similar level in Firefox as it was when I was using IE. The amount of spam received in Yahoo Mail seems to be equivalent as well.

Disabling Firefox plug-in Coupons, Inc. Coupon Printer 5.0.2.5 was easy to do and seems to have helped a lot right away.

Before switching from IE to Firefox I was already an avid user of all resources offered by the FTC website, which I continue to find quite helpful: http://www.consumer.ftc.gov/articles/0262-stopping-unsolicited-mail-phone-calls-and-email

The malware scanners list provided is very good. I was unfamiliar with it and agree it is a good approach to run different ones. I use Norton, so unfortunately I was unable to run them all as there were incompatibilities and I had concerns about disabling Norton. I ran a few and, so far, no malware problems detected.

AdBlock Plus was quite effective. However, I am not impressed with the fact that companies are paying them for the privilege of not blocking their ads. In my view an ad is an ad and companies should not be able to “pay their way out”. I wish the "page real estate" would somehow be given back to the email user though, instead of having a blank space in the area where the ad was removed. It would be nice to have that extra area incorporated in the email for a better view. Nevertheless, I will take the blank space instead of the ad...

Thank you both for the help provided!

Nice reply, thanks.

If you have any problems or concerns with AdBlock Plus you could give uBlock Origin a try. I've been a happy user of AdBlock Plus for a long time but recently switched, without problems, to uBlock Origin, said to be lighter on memory and cpu.

https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/?src=search