It's not just that it's no good, it may actually be bad for your baby's language development:
Educational videos designed to stimulate young minds, like “Baby Einstein” and “Brainy Baby,” may actually impede language development, according to a new study published this week in the Journal of Pediatrics. The DVDs have become one of the most popular educational tools for parents, with promises to build the vocabulary and enhance the cognitive development of babies as young as 3 months old. The baby-brain industry now represents about $20 billion a year, according to Susan Gregory Thomas, author of "Buy Buy Baby" (Houghton Mifflin, 2007). But the claims of these manufacturers are largely unsubstantiated. And the new study says they may do more harm than good.
Researchers at the University of Washington and Seattle Children’s Hospital Research Institute reported that for every hour infants 8-16 months old spent watching such programs, they understood an average of 6 to 8 fewer words than other infants who were not exposed to the videos. (Baby DVDs and videos had no positive or negative effect on the vocabularies of toddlers 17 to 24 months of age, researchers said.) One thousand families were surveyed about how much their kids watched the educational DVDs, educational television programs like “Sesame Street” and noneducational programming like “Sponge Bob” or “Oprah.” Researchers said that the results suggested that these DVDs are a poor substitute for warm human social interaction, when it comes to learning language.[...]
Programs like "Sesame Street" (or its Indian version "Gali Gali Simsim") work on a different principle. Here's a segment from the interview with the study's lead author and associate professor of pediatrics at the University of Washington, , Frederick Zimmerman:
What’s the difference between the content of something like Baby Einstein and traditional educational television programs like “Sesame Street” and “Blue's Clues”?
Shows that are educational have a specific educational agenda. In other words, they have learning objectives for every segment of the show. “Sesame Street,” for example, if they decide that a particular segment should teach the child the letter J, they’ll design it from the ground up with that learning objective in mind. Then they’ll test it with real children to see if they really do in fact learn to recognize the letter J. And if it doesn’t work, they’ll trash that segment and start again. Baby videos claim to be educational but they don’t go through that process—they don’t develop learning objectives and they don’t go through rigorous testing.