M.J. said:
WWJ in Detroit is making two big changes next week. First, they are going to drop the CBS Detroit branding, and call themselves WWJ-TV (a la WBZ Boston). Second, they are adding local weathercasts from former WXYZ meterologist Jim Madaus at 11 PM, and there will be improved weather reports during The Early Show. Not a newscast, but it's a start.
From the Detroit News:
http://www.detnews.com/apps/pbcs.dll/article?AID=/20080101/ENT10/801010343
IIRC, the original WWJ-TV was Channel 4 in Detroit until the 1970's, when a trade was made for WMAL-TV (now Gannett's WUSA) in Washington. FCC rules at the time forbid callsign sharing between different owners, so WWJ-TV became WDIV-TV.
CBS bought Channel 62 in Detroit during the Fox/New World debacle (A scene that was about to be repeated here in Atlanta until a last minute deal occurred), and changed the callsign to WWJ-TV to match the calls of WWJ-AM.
They are using the heritage of three-letter callsigns to help out the station. However, this will backfire severly on CBS since they are using a recycled callsign. Older people (60+) who would remember WWJ-TV being Channel 4 might see or hear an ad for "Survivor" or "60 Minutes", and tune to WDIV (NBC) instead thinking they will see CBS programs there. Since WWJ-TV has not promoted the station by its callsign, no confusion has arisen yet (most people probably are not aware of the stations callsign).
This in contrast to WBZ-TV/Boston, where the callsign is original to the station. Everyone familiar with Boston TV associates WBZ and Channel 4 together in that market, so going only by the callsign might work (but people not familiar with that market might not know that WBZ is on channel 4, since they are not marketing their dial position).
If they want to promote the station by it's callsign, they need to change it (since they don't own another three-letter callsign radio station east of the Mississippi, it would have to be a four-letter callsign)
Not everyone with a hertiage three-letter callsign can be a WSB-TV Atlanta, with monster ratings, a loyal following, and a stable anchor staff (the lead anchor, Monica Pearson (Monica Kaufman until 2006 when she remarried) has been in that seat for 33 years).