Related Clues:
- E-mail often caught in filters
- WWII staple
- Sunday paper inserts
- Web site banners
- Newspapers need 'em
- Unwelcome letters
- Promotions
- E-mail woe
- Spots of a sort
- Thirty-second spots
- In-box junk
- Hormel canned it in 1937; Congress, in 2003
- Billboards, essentially
- Blogger's revenue source
- Too much of e-mail